The context depends on the SQL mode.

Implemented a few more builders.
Improved some fragments and statement types.
Fixed the noAlias option in FieldFragment.
Reordered CREATE statements's options.
Updated contexts definitions.
Fixed typos. Improved tests.

24 files changed, 750 insertions, 215 deletions

diff --git a/src/Context.php b/src/Context.php
index 699d800..d42211f 100644
--- a/src/Context.php
+++ b/src/Context.php
@@ -110,6 +110,14 @@ abstract class Context
         '('   => 16, ')'    => 16, '.'   => 16,  ','  => 16,
     );
 
+    /**
+     * The mode of the MySQL server that will be used in lexing, parsing and
+     * building the statements.
+     *
+     * @var int
+     */
+    public static $MODE = 0;
+
     /*
      * Server SQL Modes
      * https://dev.mysql.com/doc/refman/5.0/en/sql-mode.html
@@ -413,6 +421,44 @@ abstract class Context
         self::$loadedContext = $context;
         self::$KEYWORDS = $context::$KEYWORDS;
     }
+
+    /**
+     * Sets the SQL mode.
+     *
+     * @param string $mode The list of modes. If empty, the mode is reset.
+     */
+    public static function setMode($mode = '')
+    {
+        static::$MODE = 0;
+        if (empty($mode)) {
+            return;
+        }
+        $mode = explode(',', $mode);
+        foreach ($mode as $m) {
+            static::$MODE |= constant('static::' . $m);
+        }
+    }
+
+    /**
+     * Escapes the symbol by adding surrounding backticks.
+     *
+     * @param array|string $str The string to be escaped.
+     *
+     * @return string
+     */
+    public static function escape($str)
+    {
+        if (is_array($str)) {
+            foreach ($str as $key => $value) {
+                $str[$key] = static::escape($value);
+            }
+            return $str;
+        }
+        if (static::$MODE & Context::ANSI_QUOTES) {
+            return '"' . str_replace('"', '""', $str) . '"';
+        }
+        return '`' . str_replace('`', '``', $str) . '`';
+    }
 }
 
 // Initializng the default context.
diff --git a/src/Contexts/ContextMySql50000.php b/src/Contexts/ContextMySql50000.php
index 26afac1..dc2759a 100644
--- a/src/Contexts/ContextMySql50000.php
+++ b/src/Contexts/ContextMySql50000.php
@@ -143,14 +143,14 @@ class ContextMySql50000 extends Context
         'MINUTE_MICROSECOND' => 3, 'NO_WRITE_TO_BINLOG' => 3, 'SECOND_MICROSECOND' => 3,
         'SQL_CALC_FOUND_ROWS' => 3,
 
-        'NOT NULL' => 5, 'SET NULL' => 5,
-        'NO ACTION' => 5, 'ON DELETE' => 5, 'ON UPDATE' => 5,
-        'CHARACTER SET' => 5, 'IF NOT EXISTS' => 5,
-        'DATA DIRECTORY' => 5,
-        'DEFAULT COLLATE' => 5, 'INDEX DIRECTORY' => 5,
-        'DEFAULT CHARACTER SET' => 5,
-
-        'GROUP BY' => 7, 'ORDER BY' => 7,
+        'GROUP BY' => 7, 'NOT NULL' => 7, 'ORDER BY' => 7, 'SET NULL' => 7,
+        'IF EXISTS' => 7, 'NO ACTION' => 7, 'ON DELETE' => 7, 'ON UPDATE' => 7,
+        'OR REPLACE' => 7,
+        'SQL SECURITY' => 7,
+        'CHARACTER SET' => 7, 'IF NOT EXISTS' => 7,
+        'DATA DIRECTORY' => 7,
+        'DEFAULT COLLATE' => 7, 'INDEX DIRECTORY' => 7,
+        'DEFAULT CHARACTER SET' => 7,
 
         'XML' => 9,
         'ENUM' => 9, 'TEXT' => 9,
@@ -168,18 +168,18 @@ class ContextMySql50000 extends Context
         'CHARACTER' => 11, 'MEDIUMINT' => 11, 'VARBINARY' => 11,
         'MEDIUMBLOB' => 11, 'MEDIUMTEXT' => 11,
 
-        'BINARY VARYING' => 13,
+        'BINARY VARYING' => 15,
 
         'KEY' => 19,
         'INDEX' => 19,
         'UNIQUE' => 19,
 
-        'INDEX KEY' => 21,
-        'UNIQUE KEY' => 21,
-        'FOREIGN KEY' => 21, 'PRIMARY KEY' => 21, 'SPATIAL KEY' => 21,
-        'FULLTEXT KEY' => 21, 'UNIQUE INDEX' => 21,
-        'SPATIAL INDEX' => 21,
-        'FULLTEXT INDEX' => 21,
+        'INDEX KEY' => 23,
+        'UNIQUE KEY' => 23,
+        'FOREIGN KEY' => 23, 'PRIMARY KEY' => 23, 'SPATIAL KEY' => 23,
+        'FULLTEXT KEY' => 23, 'UNIQUE INDEX' => 23,
+        'SPATIAL INDEX' => 23,
+        'FULLTEXT INDEX' => 23,
 
         'X' => 33, 'Y' => 33,
         'LN' => 33, 'PI' => 33,
@@ -258,7 +258,7 @@ class ContextMySql50000 extends Context
         'LOCALTIMESTAMP' => 35,
         'CURRENT_TIMESTAMP' => 35,
 
-        'NOT IN' => 37,
+        'NOT IN' => 39,
 
         'DATE' => 41, 'TIME' => 41, 'YEAR' => 41,
         'TIMESTAMP' => 41,
diff --git a/src/Contexts/ContextMySql50100.php b/src/Contexts/ContextMySql50100.php
index 23c619b..82db684 100644
--- a/src/Contexts/ContextMySql50100.php
+++ b/src/Contexts/ContextMySql50100.php
@@ -154,14 +154,14 @@ class ContextMySql50100 extends Context
         'SQL_CALC_FOUND_ROWS' => 3,
         'MASTER_SSL_VERIFY_SERVER_CERT' => 3,
 
-        'NOT NULL' => 5, 'SET NULL' => 5,
-        'NO ACTION' => 5, 'ON DELETE' => 5, 'ON UPDATE' => 5,
-        'CHARACTER SET' => 5, 'IF NOT EXISTS' => 5,
-        'DATA DIRECTORY' => 5,
-        'DEFAULT COLLATE' => 5, 'INDEX DIRECTORY' => 5,
-        'DEFAULT CHARACTER SET' => 5,
-
-        'GROUP BY' => 7, 'ORDER BY' => 7,
+        'GROUP BY' => 7, 'NOT NULL' => 7, 'ORDER BY' => 7, 'SET NULL' => 7,
+        'IF EXISTS' => 7, 'NO ACTION' => 7, 'ON DELETE' => 7, 'ON UPDATE' => 7,
+        'OR REPLACE' => 7,
+        'SQL SECURITY' => 7,
+        'CHARACTER SET' => 7, 'IF NOT EXISTS' => 7,
+        'DATA DIRECTORY' => 7,
+        'DEFAULT COLLATE' => 7, 'INDEX DIRECTORY' => 7,
+        'DEFAULT CHARACTER SET' => 7,
 
         'XML' => 9,
         'ENUM' => 9, 'TEXT' => 9,
@@ -179,18 +179,18 @@ class ContextMySql50100 extends Context
         'CHARACTER' => 11, 'MEDIUMINT' => 11, 'VARBINARY' => 11,
         'MEDIUMBLOB' => 11, 'MEDIUMTEXT' => 11,
 
-        'BINARY VARYING' => 13,
+        'BINARY VARYING' => 15,
 
         'KEY' => 19,
         'INDEX' => 19,
         'UNIQUE' => 19,
 
-        'INDEX KEY' => 21,
-        'UNIQUE KEY' => 21,
-        'FOREIGN KEY' => 21, 'PRIMARY KEY' => 21, 'SPATIAL KEY' => 21,
-        'FULLTEXT KEY' => 21, 'UNIQUE INDEX' => 21,
-        'SPATIAL INDEX' => 21,
-        'FULLTEXT INDEX' => 21,
+        'INDEX KEY' => 23,
+        'UNIQUE KEY' => 23,
+        'FOREIGN KEY' => 23, 'PRIMARY KEY' => 23, 'SPATIAL KEY' => 23,
+        'FULLTEXT KEY' => 23, 'UNIQUE INDEX' => 23,
+        'SPATIAL INDEX' => 23,
+        'FULLTEXT INDEX' => 23,
 
         'X' => 33, 'Y' => 33,
         'LN' => 33, 'PI' => 33,
@@ -280,7 +280,7 @@ class ContextMySql50100 extends Context
         'LOCALTIMESTAMP' => 35,
         'CURRENT_TIMESTAMP' => 35,
 
-        'NOT IN' => 37,
+        'NOT IN' => 39,
 
         'DATE' => 41, 'TIME' => 41, 'YEAR' => 41,
         'TIMESTAMP' => 41,
diff --git a/src/Contexts/ContextMySql50500.php b/src/Contexts/ContextMySql50500.php
index 03105ab..e338232 100644
--- a/src/Contexts/ContextMySql50500.php
+++ b/src/Contexts/ContextMySql50500.php
@@ -159,14 +159,14 @@ class ContextMySql50500 extends Context
         'SQL_CALC_FOUND_ROWS' => 3,
         'MASTER_SSL_VERIFY_SERVER_CERT' => 3,
 
-        'NOT NULL' => 5, 'SET NULL' => 5,
-        'NO ACTION' => 5, 'ON DELETE' => 5, 'ON UPDATE' => 5,
-        'CHARACTER SET' => 5, 'IF NOT EXISTS' => 5,
-        'DATA DIRECTORY' => 5,
-        'DEFAULT COLLATE' => 5, 'INDEX DIRECTORY' => 5,
-        'DEFAULT CHARACTER SET' => 5,
-
-        'GROUP BY' => 7, 'ORDER BY' => 7,
+        'GROUP BY' => 7, 'NOT NULL' => 7, 'ORDER BY' => 7, 'SET NULL' => 7,
+        'IF EXISTS' => 7, 'NO ACTION' => 7, 'ON DELETE' => 7, 'ON UPDATE' => 7,
+        'OR REPLACE' => 7,
+        'SQL SECURITY' => 7,
+        'CHARACTER SET' => 7, 'IF NOT EXISTS' => 7,
+        'DATA DIRECTORY' => 7,
+        'DEFAULT COLLATE' => 7, 'INDEX DIRECTORY' => 7,
+        'DEFAULT CHARACTER SET' => 7,
 
         'XML' => 9,
         'ENUM' => 9, 'TEXT' => 9,
@@ -184,18 +184,18 @@ class ContextMySql50500 extends Context
         'CHARACTER' => 11, 'MEDIUMINT' => 11, 'VARBINARY' => 11,
         'MEDIUMBLOB' => 11, 'MEDIUMTEXT' => 11,
 
-        'BINARY VARYING' => 13,
+        'BINARY VARYING' => 15,
 
         'KEY' => 19,
         'INDEX' => 19,
         'UNIQUE' => 19,
 
-        'INDEX KEY' => 21,
-        'UNIQUE KEY' => 21,
-        'FOREIGN KEY' => 21, 'PRIMARY KEY' => 21, 'SPATIAL KEY' => 21,
-        'FULLTEXT KEY' => 21, 'UNIQUE INDEX' => 21,
-        'SPATIAL INDEX' => 21,
-        'FULLTEXT INDEX' => 21,
+        'INDEX KEY' => 23,
+        'UNIQUE KEY' => 23,
+        'FOREIGN KEY' => 23, 'PRIMARY KEY' => 23, 'SPATIAL KEY' => 23,
+        'FULLTEXT KEY' => 23, 'UNIQUE INDEX' => 23,
+        'SPATIAL INDEX' => 23,
+        'FULLTEXT INDEX' => 23,
 
         'X' => 33, 'Y' => 33,
         'LN' => 33, 'PI' => 33,
@@ -284,7 +284,7 @@ class ContextMySql50500 extends Context
         'LOCALTIMESTAMP' => 35,
         'CURRENT_TIMESTAMP' => 35,
 
-        'NOT IN' => 37,
+        'NOT IN' => 39,
 
         'DATE' => 41, 'TIME' => 41, 'YEAR' => 41,
         'TIMESTAMP' => 41,
diff --git a/src/Contexts/ContextMySql50600.php b/src/Contexts/ContextMySql50600.php
index 91978cb..780ea52 100644
--- a/src/Contexts/ContextMySql50600.php
+++ b/src/Contexts/ContextMySql50600.php
@@ -165,14 +165,14 @@ class ContextMySql50600 extends Context
         'SQL_CALC_FOUND_ROWS' => 3,
         'MASTER_SSL_VERIFY_SERVER_CERT' => 3,
 
-        'NOT NULL' => 5, 'SET NULL' => 5,
-        'NO ACTION' => 5, 'ON DELETE' => 5, 'ON UPDATE' => 5,
-        'CHARACTER SET' => 5, 'IF NOT EXISTS' => 5,
-        'DATA DIRECTORY' => 5,
-        'DEFAULT COLLATE' => 5, 'INDEX DIRECTORY' => 5,
-        'DEFAULT CHARACTER SET' => 5,
-
-        'GROUP BY' => 7, 'ORDER BY' => 7,
+        'GROUP BY' => 7, 'NOT NULL' => 7, 'ORDER BY' => 7, 'SET NULL' => 7,
+        'IF EXISTS' => 7, 'NO ACTION' => 7, 'ON DELETE' => 7, 'ON UPDATE' => 7,
+        'OR REPLACE' => 7,
+        'SQL SECURITY' => 7,
+        'CHARACTER SET' => 7, 'IF NOT EXISTS' => 7,
+        'DATA DIRECTORY' => 7,
+        'DEFAULT COLLATE' => 7, 'INDEX DIRECTORY' => 7,
+        'DEFAULT CHARACTER SET' => 7,
 
         'XML' => 9,
         'ENUM' => 9, 'TEXT' => 9,
@@ -190,18 +190,18 @@ class ContextMySql50600 extends Context
         'CHARACTER' => 11, 'MEDIUMINT' => 11, 'VARBINARY' => 11,
         'MEDIUMBLOB' => 11, 'MEDIUMTEXT' => 11,
 
-        'BINARY VARYING' => 13,
+        'BINARY VARYING' => 15,
 
         'KEY' => 19,
         'INDEX' => 19,
         'UNIQUE' => 19,
 
-        'INDEX KEY' => 21,
-        'UNIQUE KEY' => 21,
-        'FOREIGN KEY' => 21, 'PRIMARY KEY' => 21, 'SPATIAL KEY' => 21,
-        'FULLTEXT KEY' => 21, 'UNIQUE INDEX' => 21,
-        'SPATIAL INDEX' => 21,
-        'FULLTEXT INDEX' => 21,
+        'INDEX KEY' => 23,
+        'UNIQUE KEY' => 23,
+        'FOREIGN KEY' => 23, 'PRIMARY KEY' => 23, 'SPATIAL KEY' => 23,
+        'FULLTEXT KEY' => 23, 'UNIQUE INDEX' => 23,
+        'SPATIAL INDEX' => 23,
+        'FULLTEXT INDEX' => 23,
 
         'X' => 33, 'Y' => 33,
         'LN' => 33, 'PI' => 33,
@@ -315,7 +315,7 @@ class ContextMySql50600 extends Context
         'LOCALTIMESTAMP' => 35,
         'CURRENT_TIMESTAMP' => 35,
 
-        'NOT IN' => 37,
+        'NOT IN' => 39,
 
         'DATE' => 41, 'TIME' => 41, 'YEAR' => 41,
         'TIMESTAMP' => 41,
diff --git a/src/Contexts/ContextMySql50700.php b/src/Contexts/ContextMySql50700.php
index 0837409..6a3cfd6 100644
--- a/src/Contexts/ContextMySql50700.php
+++ b/src/Contexts/ContextMySql50700.php
@@ -173,14 +173,14 @@ class ContextMySql50700 extends Context
         'SQL_CALC_FOUND_ROWS' => 3,
         'MASTER_SSL_VERIFY_SERVER_CERT' => 3,
 
-        'NOT NULL' => 5, 'SET NULL' => 5,
-        'NO ACTION' => 5, 'ON DELETE' => 5, 'ON UPDATE' => 5,
-        'CHARACTER SET' => 5, 'IF NOT EXISTS' => 5,
-        'DATA DIRECTORY' => 5,
-        'DEFAULT COLLATE' => 5, 'INDEX DIRECTORY' => 5,
-        'DEFAULT CHARACTER SET' => 5,
-
-        'GROUP BY' => 7, 'ORDER BY' => 7,
+        'GROUP BY' => 7, 'NOT NULL' => 7, 'ORDER BY' => 7, 'SET NULL' => 7,
+        'IF EXISTS' => 7, 'NO ACTION' => 7, 'ON DELETE' => 7, 'ON UPDATE' => 7,
+        'OR REPLACE' => 7,
+        'SQL SECURITY' => 7,
+        'CHARACTER SET' => 7, 'IF NOT EXISTS' => 7,
+        'DATA DIRECTORY' => 7,
+        'DEFAULT COLLATE' => 7, 'INDEX DIRECTORY' => 7,
+        'DEFAULT CHARACTER SET' => 7,
 
         'XML' => 9,
         'ENUM' => 9, 'TEXT' => 9,
@@ -198,18 +198,18 @@ class ContextMySql50700 extends Context
         'CHARACTER' => 11, 'MEDIUMINT' => 11, 'VARBINARY' => 11,
         'MEDIUMBLOB' => 11, 'MEDIUMTEXT' => 11,
 
-        'BINARY VARYING' => 13,
+        'BINARY VARYING' => 15,
 
         'KEY' => 19,
         'INDEX' => 19,
         'UNIQUE' => 19,
 
-        'INDEX KEY' => 21,
-        'UNIQUE KEY' => 21,
-        'FOREIGN KEY' => 21, 'PRIMARY KEY' => 21, 'SPATIAL KEY' => 21,
-        'FULLTEXT KEY' => 21, 'UNIQUE INDEX' => 21,
-        'SPATIAL INDEX' => 21,
-        'FULLTEXT INDEX' => 21,
+        'INDEX KEY' => 23,
+        'UNIQUE KEY' => 23,
+        'FOREIGN KEY' => 23, 'PRIMARY KEY' => 23, 'SPATIAL KEY' => 23,
+        'FULLTEXT KEY' => 23, 'UNIQUE INDEX' => 23,
+        'SPATIAL INDEX' => 23,
+        'FULLTEXT INDEX' => 23,
 
         'X' => 33, 'Y' => 33,
         'LN' => 33, 'PI' => 33,
@@ -327,7 +327,7 @@ class ContextMySql50700 extends Context
         'LOCALTIMESTAMP' => 35,
         'CURRENT_TIMESTAMP' => 35,
 
-        'NOT IN' => 37,
+        'NOT IN' => 39,
 
         'DATE' => 41, 'TIME' => 41, 'YEAR' => 41,
         'TIMESTAMP' => 41,
diff --git a/src/Fragments/AlterFragment.php b/src/Fragments/AlterFragment.php
new file mode 100644
index 0000000..54338f9
--- /dev/null
+++ b/src/Fragments/AlterFragment.php
@@ -0,0 +1,201 @@
+<?php
+
+/**
+ * Parses a reference to a field.
+ *
+ * @package    SqlParser
+ * @subpackage Fragments
+ */
+namespace SqlParser\Fragments;
+
+use SqlParser\Fragment;
+use SqlParser\Parser;
+use SqlParser\Token;
+use SqlParser\TokensList;
+
+/**
+ * Parses a reference to a field.
+ *
+ * @category   Fragments
+ * @package    SqlParser
+ * @subpackage Fragments
+ * @author     Dan Ungureanu <udan1107@gmail.com>
+ * @license    http://opensource.org/licenses/GPL-2.0 GNU Public License
+ */
+class AlterFragment extends Fragment
+{
+
+    /**
+     * All alter operations.
+     *
+     * @var array
+     */
+    public static $OPTIONS = array(
+        'ADD'                           => 3,
+        'ALTER'                         => 3,
+        'ANALYZE'                       => 3,
+        'CHANGE'                        => 3,
+        'CHECK'                         => 3,
+        'COALESCE'                      => 3,
+        'CONVERT'                       => 3,
+        'DISABLE'                       => 3,
+        'DISCARD'                       => 3,
+        'DROP'                          => 3,
+        'ENABLE'                        => 3,
+        'IMPORT'                        => 3,
+        'MODIFY'                        => 3,
+        'OPTIMIZE'                      => 3,
+        'ORDER'                         => 3,
+        'PARTITION'                     => 3,
+        'REBUILD'                       => 3,
+        'REMOVE'                        => 3,
+        'RENAME'                        => 3,
+        'REORGANIZE'                    => 3,
+        'REPAIR'                        => 3,
+
+        'COLUMN'                        => 4,
+        'CONSTRAINT'                    => 4,
+        'DEFAULT'                       => 4,
+        'TO'                            => 4,
+        'BY'                            => 4,
+        'FOREIGN'                       => 4,
+        'FULLTEXT'                      => 4,
+        'KEY'                           => 4,
+        'KEYS'                          => 4,
+        'PARTITIONING'                  => 4,
+        'PRIMARY KEY'                   => 4,
+        'SPATIAL'                       => 4,
+        'TABLESPACE'                    => 4,
+        'INDEX'                         => 4,
+
+        'DEFAULT CHARACTER SET'         => array(5, 'var'),
+
+        'COLLATE'                       => array(6, 'var'),
+    );
+
+    /**
+     * Options of this operation.
+     *
+     * @var OptionsFragment
+     */
+    public $options;
+
+    /**
+     * The altered field.
+     *
+     * @var FieldFragment
+     */
+    public $field;
+
+    /**
+     * Unparsed tokens.
+     *
+     * @var Token[]
+     */
+    public $unknown = array();
+
+    /**
+     * @param Parser     $parser  The parser that serves as context.
+     * @param TokensList $list    The list of tokens that are being parsed.
+     * @param array      $options Parameters for parsing.
+     *
+     * @return AlterFragment
+     */
+    public static function parse(Parser $parser, TokensList $list, array $options = array())
+    {
+        $ret = new AlterFragment();
+
+        /**
+         * Counts brackets.
+         * @var int
+         */
+        $brackets = 0;
+
+        /**
+         * The state of the parser.
+         *
+         * Below are the states of the parser.
+         *
+         *      0 ---------------------[ options ]---------------------> 1
+         *
+         *      1 ----------------------[ field ]----------------------> 2
+         *
+         *      2 -------------------------[ , ]-----------------------> 0
+         *
+         * @var int
+         */
+        $state = 0;
+
+        for (; $list->idx < $list->count; ++$list->idx) {
+            /**
+             * Token parsed at this moment.
+             * @var Token
+             */
+            $token = $list->tokens[$list->idx];
+
+            // End of statement.
+            if ($token->type === Token::TYPE_DELIMITER) {
+                break;
+            }
+
+            // Skipping whitespaces and comments.
+            if (($token->type === Token::TYPE_WHITESPACE) || ($token->type === Token::TYPE_COMMENT)) {
+                if ($state !== 2) {
+                    // State 2 parses the unknown part which must include whitespaces as well.
+                    continue;
+                }
+            }
+
+            if ($state === 0) {
+                $ret->options = OptionsFragment::parse($parser, $list, static::$OPTIONS);
+                $state = 1;
+            } elseif ($state === 1) {
+                $ret->field = FieldFragment::parse(
+                    $parser,
+                    $list,
+                    array(
+                        'noAlias' => true,
+                        'noBrackets' => true,
+                    )
+                );
+                if ($ret->field === null) {
+                    // No field was read. We go back one token so the next
+                    // iteration will parse the same on, but in state 2.
+                    --$list->idx;
+                }
+                $state = 2;
+            } elseif ($state === 2) {
+                if ($token->type === Token::TYPE_OPERATOR) {
+                    if ($token->value === '(') {
+                        ++$brackets;
+                    } elseif ($token->value === ')') {
+                        --$brackets;
+                    } elseif ($token->value === ',') {
+                        break;
+                    }
+                }
+                $ret->unknown[] = $token;
+            }
+        }
+
+        --$list->idx;
+        return $ret;
+    }
+
+    /**
+     * @param AlterFragment $fragment The fragment to be built.
+     *
+     * @return string
+     */
+    public static function build($fragment)
+    {
+        $ret = OptionsFragment::build($fragment->options) . ' ';
+        if (!empty($fragment->field)) {
+            $ret .= FieldFragment::build($fragment->field) . ' ';
+        }
+        foreach ($fragment->unknown as $token) {
+            $ret .= $token->token;
+        }
+        return $ret;
+    }
+}
diff --git a/src/Fragments/DataTypeFragment.php b/src/Fragments/DataTypeFragment.php
index 0b9e1a8..6a44b78 100644
--- a/src/Fragments/DataTypeFragment.php
+++ b/src/Fragments/DataTypeFragment.php
@@ -35,7 +35,7 @@ class DataTypeFragment extends Fragment
         'BINARY'                        => 1,
         'CHARACTER SET'                 => array(2, 'var'),
         'CHARSET'                       => array(2, 'var'),
-        'COLLATE'                       => 3,
+        'COLLATE'                       => array(3, 'var'),
         'UNSIGNED'                      => 4,
         'ZEROFILL'                      => 5,
     );
@@ -70,6 +70,21 @@ class DataTypeFragment extends Fragment
     public $options;
 
     /**
+     * Constructor.
+     *
+     * @param string          $name       The name of this data type.
+     * @param array           $parameters The parameters (size or possible values).
+     * @param OptionsFragment $options    The options of this data type.
+     */
+    public function __construct($name = null, array $parameters = array(),
+        $options = null
+    ) {
+        $this->name = $name;
+        $this->parameters = $parameters;
+        $this->options = $options;
+    }
+
+    /**
      * @param Parser     $parser  The parser that serves as context.
      * @param TokensList $list    The list of tokens that are being parsed.
      * @param array      $options Parameters for parsing.
@@ -113,10 +128,10 @@ class DataTypeFragment extends Fragment
                 $state = 1;
             } elseif ($state === 1) {
                 if (($token->type === Token::TYPE_OPERATOR) && ($token->value === '(')) {
-                    $size = ArrayFragment::parse($parser, $list);
+                    $parameters = ArrayFragment::parse($parser, $list);
                     ++$list->idx;
                     $ret->parameters = (($ret->name === 'ENUM') || ($ret->name === 'SET')) ?
-                        $size->raw : $size->values;
+                        $parameters->raw : $parameters->values;
                 }
                 $ret->options = OptionsFragment::parse($parser, $list, static::$DATA_TYPE_OPTIONS);
                 ++$list->idx;
@@ -132,4 +147,21 @@ class DataTypeFragment extends Fragment
         --$list->idx;
         return $ret;
     }
+
+    /**
+     * @param DataTypeFragment $fragment The fragment to be built.
+     *
+     * @return string
+     */
+    public static function build($fragment)
+    {
+        $tmp = '';
+        if (!empty($fragment->parameters)) {
+            $tmp = '('. implode(', ', $fragment->parameters) . ')';
+        }
+        return trim(
+            $fragment->name . ' ' . $tmp . ' '
+            . OptionsFragment::build($fragment->options)
+        );
+    }
 }
diff --git a/src/Fragments/FieldDefFragment.php b/src/Fragments/FieldDefFragment.php
index 6c5771e..9f43fcc 100644
--- a/src/Fragments/FieldDefFragment.php
+++ b/src/Fragments/FieldDefFragment.php
@@ -92,6 +92,29 @@ class FieldDefFragment extends Fragment
     public $options;
 
     /**
+     * Constructor.
+     *
+     * @param string                       $name         The name of the field.
+     * @param OptionsFragment              $options      The options of this field.
+     * @param DataTypeFragment|KeyFragment $type         The data type of this field or the key.
+     * @param bool                         $isConstraint Whether this field is a constraint or not.
+     * @param ReferencesKeyword            $references   References.
+     */
+    public function __construct($name = null, $options = null, $type = null,
+        $isConstraint = false, $references = null
+    ) {
+        $this->name = $name;
+        $this->options = $options;
+        if ($type instanceof DataTypeFragment) {
+            $this->type = $type;
+        } elseif ($type instanceof KeyFragment) {
+            $this->key = $type;
+            $this->isConstraint = $isConstraint;
+            $this->references = $references;
+        }
+    }
+
+    /**
      * @param Parser     $parser  The parser that serves as context.
      * @param TokensList $list    The list of tokens that are being parsed.
      * @param array      $options Parameters for parsing.
@@ -200,4 +223,42 @@ class FieldDefFragment extends Fragment
         return $ret;
 
     }
+
+    /**
+     * @param FieldDefFragment[] $fragment The fragment to be built.
+     *
+     * @return string
+     */
+    public static function build($fragment)
+    {
+        $ret = array();
+        foreach ($fragment as $f) {
+            $tmp = '';
+
+            if ($f->isConstraint) {
+                $tmp .= 'CONSTRAINT ';
+            }
+
+            if (!empty($f->name)) {
+                $tmp .= Context::escape($f->name) . ' ';
+            }
+
+            if (!empty($f->type)) {
+                $tmp .= DataTypeFragment::build($f->type) . ' ';
+            }
+
+            if (!empty($f->key)) {
+                $tmp .= KeyFragment::build($f->key) . ' ';
+            }
+
+            if (!empty($f->references)) {
+                $tmp .= 'REFERENCES ' . ReferencesKeyword::build($f->references) . ' ';
+            }
+
+            $tmp .= OptionsFragment::build($f->options);
+
+            $ret[] = trim($tmp);
+        }
+        return '(' . implode(', ', $ret) . ')';
+    }
 }
diff --git a/src/Fragments/FieldFragment.php b/src/Fragments/FieldFragment.php
index edd0a2b..c33a7d7 100644
--- a/src/Fragments/FieldFragment.php
+++ b/src/Fragments/FieldFragment.php
@@ -8,6 +8,7 @@
  */
 namespace SqlParser\Fragments;
 
+use SqlParser\Context;
 use SqlParser\Fragment;
 use SqlParser\Parser;
 use SqlParser\Token;
@@ -168,7 +169,7 @@ class FieldFragment extends Fragment
                 if (($isExpr) && (!$alias)) {
                     $ret->expr .= $token->token;
                 }
-                if (($alias === 0) && (!$isExpr) && (!$period) && (!empty($ret->expr))) {
+                if (($alias === 0) && (empty($options['noAlias'])) && (!$isExpr) && (!$period) && (!empty($ret->expr))) {
                     $alias = 1;
                 }
                 continue;
@@ -194,14 +195,14 @@ class FieldFragment extends Fragment
             }
 
             if ($token->type === Token::TYPE_OPERATOR) {
-                if ((!empty($options['noBrackets'])) &&
-                    (($token->value === '(') || ($token->value === ')'))
+                if ((!empty($options['noBrackets']))
+                    && (($token->value === '(') || ($token->value === ')'))
                 ) {
                     break;
                 }
                 if ($token->value === '(') {
                     ++$brackets;
-                    // We don't check to see if `$prev` is `true` (open bracke
+                    // We don't check to see if `$prev` is `true` (open bracket
                     // was found before) because the brackets count is one (the
                     // only bracket we found is this one).
                     if (($brackets === 1) && (empty($ret->function)) && ($prev !== null) && ($prev !== true)) {
@@ -246,13 +247,20 @@ class FieldFragment extends Fragment
                         }
                         $ret->database = $ret->table;
                         $ret->table = $ret->column;
+                        $ret->column = null;
                         $period = true;
                     } else {
                         // We found the name of a column (or table if column
                         // field should be skipped; used to parse table names).
                         if (!empty($options['skipColumn'])) {
+                            if (!empty($ret->table)) {
+                                break;
+                            }
                             $ret->table = $token->value;
                         } else {
+                            if (!empty($ret->column)) {
+                                break;
+                            }
                             $ret->column = $token->value;
                         }
                         $period = false;
@@ -317,11 +325,11 @@ class FieldFragment extends Fragment
             if (!empty($fragment->column)) {
                 $fields[] = $fragment->column;
             }
-            $ret = implode('.', $fields);
+            $ret = implode('.', Context::escape($fields));
         }
 
         if (!empty($fragment->alias)) {
-            $ret .= ' AS ' . $fragment->alias;
+            $ret .= ' AS ' . Context::escape($fragment->alias);
         }
 
         return $ret;
diff --git a/src/Fragments/KeyFragment.php b/src/Fragments/KeyFragment.php
index d84c9f6..1964cd2 100644
--- a/src/Fragments/KeyFragment.php
+++ b/src/Fragments/KeyFragment.php
@@ -67,6 +67,16 @@ class KeyFragment extends Fragment
      */
     public $options;
 
+
+    public function __construct($name = null, array $columns = array(),
+        $type = null, $options = null
+    ) {
+        $this->name = $name;
+        $this->columns = $columns;
+        $this->type = $type;
+        $this->options = $options;
+    }
+
     /**
      * @param Parser     $parser  The parser that serves as context.
      * @param TokensList $list    The list of tokens that are being parsed.
@@ -131,6 +141,21 @@ class KeyFragment extends Fragment
 
         --$list->idx;
         return $ret;
+    }
 
+    /**
+     * @param KeyFragment $fragment The fragment to be built.
+     *
+     * @return string
+     */
+    public static function build($fragment)
+    {
+        $ret = $fragment->type . ' ';
+        if (!empty($fragment->name)) {
+            $ret .= Context::escape($fragment->name) . ' ';
+        }
+        $ret .= '(' . implode(', ', Context::escape($fragment->columns)) . ')';
+        $ret .= OptionsFragment::build($fragment->options);
+        return trim($ret);
     }
 }
diff --git a/src/Fragments/OptionsFragment.php b/src/Fragments/OptionsFragment.php
index 00ac282..fa06b0d 100644
--- a/src/Fragments/OptionsFragment.php
+++ b/src/Fragments/OptionsFragment.php
@@ -110,7 +110,12 @@ class OptionsFragment extends Fragment
 
             if (is_array($lastOption)) {
                 if (empty($ret->options[$lastOptionId])) {
-                    $ret->options[$lastOptionId] = array('name' => $token->value, 'value' => '');
+                    $ret->options[$lastOptionId] = array(
+                        'name' => $token->value,
+                        'equal' => $lastOption[1] === 'var=',
+                        'value' => '',
+                        'value_' => '',
+                    );
                 } else {
                     if ($token->value !== '=') {
                         if ($token->value === '(') {
@@ -118,7 +123,9 @@ class OptionsFragment extends Fragment
                         } elseif ($token->value === ')') {
                             --$brackets;
                         } else {
-                            $ret->options[$lastOptionId]['value'] .= $token->value;
+                            // Raw and processed value.
+                            $ret->options[$lastOptionId]['value'] .= $token->token;
+                            $ret->options[$lastOptionId]['value_'] .= $token->value;
                         }
                         if ($brackets === 0) {
                             $lastOption = null;
@@ -144,10 +151,15 @@ class OptionsFragment extends Fragment
      */
     public static function build($fragment)
     {
+        if ((empty($fragment)) || (!is_array($fragment->options))) {
+            return '';
+        }
         $options = array();
         foreach ($fragment->options as $option) {
             if (is_array($option)) {
-                $options[] = $option['name'] . '=' . $option['value'];
+                $options[] = $option['name']
+                    . (!empty($option['equal']) ? '=' : ' ')
+                    . $option['value'];
             } else {
                 $options[] = $option;
             }
diff --git a/src/Fragments/ReferencesKeyword.php b/src/Fragments/ReferencesKeyword.php
index 8de0233..ea10d20 100644
--- a/src/Fragments/ReferencesKeyword.php
+++ b/src/Fragments/ReferencesKeyword.php
@@ -8,6 +8,7 @@
  */
 namespace SqlParser\Fragments;
 
+use SqlParser\Context;
 use SqlParser\Fragment;
 use SqlParser\Parser;
 use SqlParser\Token;
@@ -58,6 +59,20 @@ class ReferencesKeyword extends Fragment
     public $options;
 
     /**
+     * Constructor.
+     *
+     * @param string          $table   The name of the table referenced.
+     * @param array           $columns The columns referenced.
+     * @param OptionsFragment $options The options.
+     */
+    public function __construct($table = null, array $columns = array(), $options = null)
+    {
+        $this->table = $table;
+        $this->columns = $columns;
+        $this->options = $options;
+    }
+
+    /**
      * @param Parser     $parser  The parser that serves as context.
      * @param TokensList $list    The list of tokens that are being parsed.
      * @param array      $options Parameters for parsing.
@@ -117,4 +132,18 @@ class ReferencesKeyword extends Fragment
         --$list->idx;
         return $ret;
     }
+
+    /**
+     * @param ReferencesKeyword $fragment The fragment to be built.
+     *
+     * @return string
+     */
+    public static function build($fragment)
+    {
+        return trim(
+            Context::escape($fragment->table)
+            . ' (' . implode(', ', Context::escape($fragment->columns)) . ') '
+            . OptionsFragment::build($fragment->options)
+        );
+    }
 }
diff --git a/src/Lexer.php b/src/Lexer.php
index 0d0862d..01d41d8 100644
--- a/src/Lexer.php
+++ b/src/Lexer.php
@@ -290,7 +290,25 @@ class Lexer
          */
         $iEnd = $this->last;
 
+        /**
+         * Whether last parsed character is a whitespace.
+         * @var bool
+         */
+        $lastSpace = false;
+
         for ($j = 1; $j < Context::KEYWORD_MAX_LENGTH && $this->last < $this->len; ++$j, ++$this->last) {
+            // Composed keywords shouldn't have more than one whitespace between
+            // keywords.
+            if (Context::isWhitespace($this->str[$this->last])) {
+                if ($lastSpace) {
+                    --$j; // The size of the keyword didn't increase.
+                    continue;
+                } else {
+                    $lastSpace = true;
+                }
+            } else {
+                $lastSpace = false;
+            }
             $token .= $this->str[$this->last];
             if (($this->last + 1 === $this->len) || (Context::isSeparator($this->str[$this->last + 1]))) {
                 if (($flags = Context::isKeyword($token))) {
diff --git a/src/Parser.php b/src/Parser.php
index 11874fa..ff55f5f 100644
--- a/src/Parser.php
+++ b/src/Parser.php
@@ -337,10 +337,7 @@ class Parser
              * Processed statement.
              * @var Statement
              */
-            $stmt = new $class();
-
-            // Parsing the actual statement.
-            $stmt->parse($this, $this->list);
+            $stmt = new $class($this, $this->list);
 
             // The first token that is a part of this token is the next token
             // unprocessed by the previous statement.
diff --git a/src/Statement.php b/src/Statement.php
index 1591d66..5ef7aec 100644
--- a/src/Statement.php
+++ b/src/Statement.php
@@ -38,7 +38,7 @@ abstract class Statement
      *
      * @var array
      */
-    public static $CLAUSES;
+    public static $CLAUSES = array();
 
     /**
      * The options of this query.
@@ -79,7 +79,7 @@ abstract class Statement
     /**
      * Builds the statement.
      *
-     * @return void
+     * @return string
      */
     public function build()
     {
diff --git a/src/Statements/AlterStatement.php b/src/Statements/AlterStatement.php
index 81bca05..92f3744 100644
--- a/src/Statements/AlterStatement.php
+++ b/src/Statements/AlterStatement.php
@@ -9,11 +9,12 @@
 namespace SqlParser\Statements;
 
 use SqlParser\Parser;
+use SqlParser\Statement;
 use SqlParser\Token;
 use SqlParser\TokensList;
+use SqlParser\Fragments\AlterFragment;
 use SqlParser\Fragments\FieldFragment;
 use SqlParser\Fragments\OptionsFragment;
-use SqlParser\Statements\NotImplementedStatement;
 
 /**
  * `ALTER` statement.
@@ -24,7 +25,7 @@ use SqlParser\Statements\NotImplementedStatement;
  * @author     Dan Ungureanu <udan1107@gmail.com>
  * @license    http://opensource.org/licenses/GPL-2.0 GNU Public License
  */
-class AlterStatement extends NotImplementedStatement
+class AlterStatement extends Statement
 {
 
     /**
@@ -37,9 +38,9 @@ class AlterStatement extends NotImplementedStatement
     /**
      * Column affected by this statement.
      *
-     * @var FieldFragment
+     * @var AlterFragment[]
      */
-    public $altered;
+    public $altered = array();
 
     /**
      * Options of this statement.
@@ -47,83 +48,91 @@ class AlterStatement extends NotImplementedStatement
      * @var array
      */
     public static $OPTIONS = array(
-
         'ONLINE'                        => 1,
         'OFFLINE'                       => 1,
-
         'IGNORE'                        => 2,
-
-        'TABLE'                         => 3,
-
-        'ADD'                           => 4,
-        'ALTER'                         => 4,
-        'ANALYZE'                       => 4,
-        'CHANGE'                        => 4,
-        'CHECK'                         => 4,
-        'COALESCE'                      => 4,
-        'CONVERT'                       => 4,
-        'DISABLE'                       => 4,
-        'DISCARD'                       => 4,
-        'DROP'                          => 4,
-        'ENABLE'                        => 4,
-        'IMPORT'                        => 4,
-        'MODIFY'                        => 4,
-        'OPTIMIZE'                      => 4,
-        'ORDER'                         => 4,
-        'PARTITION'                     => 4,
-        'REBUILD'                       => 4,
-        'REMOVE'                        => 4,
-        'RENAME'                        => 4,
-        'REORGANIZE'                    => 4,
-        'REPAIR'                        => 4,
-
-        'COLUMN'                        => 5,
-        'CONSTRAINT'                    => 5,
-        'DEFAULT'                       => 5,
-        'TO'                            => 5,
-        'BY'                            => 5,
-        'FOREIGN'                       => 5,
-        'FULLTEXT'                      => 5,
-        'KEYS'                          => 5,
-        'PARTITIONING'                  => 5,
-        'PRIMARY KEY'                   => 5,
-        'SPATIAL'                       => 5,
-        'TABLESPACE'                    => 5,
-        'INDEX'                         => 5,
-
-        'DEFAULT CHARACTER SET'         => array(6, 'var'),
-
-        'COLLATE'                       => array(7, 'var'),
     );
 
     /**
-     * Function called after the token was processed.
-     *
-     * Extracts the name of affected column.
-     *
      * @param Parser     $parser The instance that requests parsing.
      * @param TokensList $list   The list of tokens to be parsed.
-     * @param Token      $token  The token that is being parsed.
      *
      * @return void
      */
-    public function after(Parser $parser, TokensList $list, Token $token)
+    public function parse(Parser $parser, TokensList $list)
     {
-        // Parsing operation.
-        ++$list->idx;
-        $this->options->merge(
-            OptionsFragment::parse(
-                $parser,
-                $list,
-                static::$OPTIONS
-            )
+        ++$list->idx; // Skipping `ALTER`.
+        $this->options = OptionsFragment::parse(
+            $parser,
+            $list,
+            static::$OPTIONS
         );
 
-        // Parsing affected field.
-        ++$list->idx;
-        $this->altered = FieldFragment::parse($parser, $list);
+        // Skipping `TABLE`.
+        $list->getNextOfTypeAndValue(Token::TYPE_KEYWORD, 'TABLE');
 
-        //
-        parent::after($parser, $list, $token);
+        // Parsing affected table.
+        $this->table = FieldFragment::parse(
+            $parser, $list, array(
+            'noAlias' => true,
+            'noBrackets' => true,
+            )
+        );
+        ++$list->idx; // Skipping field.
+
+        /**
+         * The state of the parser.
+         *
+         * Below are the states of the parser.
+         *
+         *      0 -----------------[ alter operation ]-----------------> 1
+         *
+         *      1 -------------------------[ , ]-----------------------> 0
+         *
+         * @var int
+         */
+        $state = 0;
+
+        for (; $list->idx < $list->count; ++$list->idx) {
+            /**
+             * Token parsed at this moment.
+             * @var Token
+             */
+            $token = $list->tokens[$list->idx];
+
+            // End of statement.
+            if ($token->type === Token::TYPE_DELIMITER) {
+                break;
+            }
+
+            // Skipping whitespaces and comments.
+            if (($token->type === Token::TYPE_WHITESPACE) || ($token->type === Token::TYPE_COMMENT)) {
+                continue;
+            }
+
+            if ($state === 0) {
+                $this->altered[] = AlterFragment::parse($parser, $list);
+                $state = 1;
+            } else if ($state === 1) {
+                if (($token->type === Token::TYPE_OPERATOR) && ($token->value === ',')) {
+                    $state = 0;
+                }
+            }
+        }
+    }
+
+    /**
+     * @return string
+     */
+    public function build()
+    {
+        $tmp = array();
+        foreach ($this->altered as $altered) {
+            $tmp[] = $altered::build($altered);
+        }
+
+        return 'ALTER ' .  OptionsFragment::build($this->options)
+            . ' TABLE ' . FieldFragment::build($this->table)
+            . ' ' . implode(', ', $tmp);
     }
 }
diff --git a/src/Statements/CreateStatement.php b/src/Statements/CreateStatement.php
index 7fd8ef0..306bfeb 100644
--- a/src/Statements/CreateStatement.php
+++ b/src/Statements/CreateStatement.php
@@ -38,30 +38,30 @@ class CreateStatement extends Statement
      */
     public static $OPTIONS = array(
 
-        'DATABASE'                      => 1,
-        'EVENT'                         => 1,
-        'FUNCTION'                      => 1,
-        'INDEX'                         => 1,
-        'PROCEDURE'                     => 1,
-        'SERVER'                        => 1,
-        'TABLE'                         => 1,
-        'TABLESPACE'                    => 1,
-        'TRIGGER'                       => 1,
-        'USER'                          => 1,
-        'VIEW'                          => 1,
-
         // CREATE TABLE
-        'TEMPORARY'                     => 2,
-        'IF NOT EXISTS'                 => 3,
+        'TEMPORARY'                     => 1,
+        'IF NOT EXISTS'                 => 2,
 
         // CREATE FUNCTION / PROCEDURE and CREATE VIEW
-        'DEFINER'                       => array(2, 'var'),
+        'DEFINER'                       => array(1, 'var='),
 
         // CREATE VIEW
-        'OR REPLACE'                    => array(3, 'var'),
-        'ALGORITHM'                     => array(4, 'var'),
-        'DEFINER'                       => array(5, 'var'),
-        'SQL SECURITY'                  => array(6, 'var'),
+        'OR REPLACE'                    => array(2, 'var='),
+        'ALGORITHM'                     => array(3, 'var='),
+        'DEFINER'                       => array(4, 'var='),
+        'SQL SECURITY'                  => array(5, 'var'),
+
+        'DATABASE'                      => 6,
+        'EVENT'                         => 6,
+        'FUNCTION'                      => 6,
+        'INDEX'                         => 6,
+        'PROCEDURE'                     => 6,
+        'SERVER'                        => 6,
+        'TABLE'                         => 6,
+        'TABLESPACE'                    => 6,
+        'TRIGGER'                       => 6,
+        'USER'                          => 6,
+        'VIEW'                          => 6,
     );
 
     /**
@@ -70,8 +70,8 @@ class CreateStatement extends Statement
      * @var array
      */
     public static $TABLE_OPTIONS = array(
-        'ENGINE'                        => array(1, 'var'),
-        'AUTO_INCREMENT'                => array(2, 'var'),
+        'ENGINE'                        => array(1, 'var='),
+        'AUTO_INCREMENT'                => array(2, 'var='),
         'AVG_ROW_LENGTH'                => array(3, 'var'),
         'DEFAULT CHARACTER SET'         => array(4, 'var'),
         'CHARACTER SET'                 => array(4, 'var'),
@@ -144,15 +144,6 @@ class CreateStatement extends Statement
     public $fields;
 
     /**
-     * The `SELECT` statement that defines this view.
-     *
-     * Used by `CREATE VIEW`.
-     *
-     * @var SelectStatement
-     */
-    public $select;
-
-    /**
      * The return data type of this routine.
      *
      * Used by `CREATE FUNCTION`.
@@ -170,15 +161,36 @@ class CreateStatement extends Statement
      */
     public $parameters;
 
-
     /**
-     * The body of this function or procedure.
+     * The body of this function or procedure. For views, it is the select
+     * statement that gets the
      *
-     * Used by `CREATE FUNCTION` and `CREATE PROCEDURE`.
+     * Used by `CREATE FUNCTION`, `CREATE PROCEDURE` and `CREATE VIEW`.
      *
      * @var Token[]
      */
-    public $body;
+    public $body = array();
+
+    /**
+     * @return string
+     */
+    public function build()
+    {
+        $tmp = '';
+        if ($this->options->has('TABLE')) {
+            $tmp = FieldDefFragment::build($this->fields);
+        } elseif ($this->options->has('VIEW')) {
+            if (!empty($this->fields)) {
+                $tmp .= ArrayFragment::build($this->fields) . ' ';
+            }
+            $tmp .= 'AS ' . TokensList::build($this->body);
+        }
+        return 'CREATE '
+            . OptionsFragment::build($this->options) . ' '
+            . FieldFragment::build($this->name) . ' '
+            . $tmp . ' '
+            . OptionsFragment::build($this->entityOptions);
+    }
 
     /**
      * @param Parser     $parser The instance that requests parsing.
@@ -258,11 +270,17 @@ class CreateStatement extends Statement
                 --$list->idx; // getNext() also goes forward one field.
                 $this->fields = ArrayFragment::parse($parser, $list);
                 ++$list->idx; // Skipping last token from the array.
-                $token = $list->getNext();
+                $list->getNext();
             }
 
-            // Parsing the 'SELECT' statement.
-            $this->select = new SelectStatement($parser, $list);
+            // Parsing the `AS` keyword.
+            for (; $list->idx < $list->count; ++$list->idx) {
+                $token = $list->tokens[$list->idx];
+                if ($token->type === Token::TYPE_DELIMITER) {
+                    break;
+                }
+                $this->body[] = $token;
+            }
         }
     }
 }
diff --git a/src/Statements/DropStatement.php b/src/Statements/DropStatement.php
index babf18a..f0cd1ce 100644
--- a/src/Statements/DropStatement.php
+++ b/src/Statements/DropStatement.php
@@ -46,6 +46,21 @@ class DropStatement extends Statement
     );
 
     /**
+     * The clauses of this statement, in order.
+     *
+     * @see Statement::$CLAUSES
+     *
+     * @var array
+     */
+    public static $CLAUSES = array(
+        'DROP'                          => array('DROP',        2),
+        // Used for options.
+        '_OPTIONS'                      => array('_OPTIONS',    1),
+        // Used for select expressions.
+        'DROP_'                         => array('DROP',        1),
+    );
+
+    /**
      * Dropped elements.
      *
      * @var FieldFragment[]
diff --git a/src/Statements/NotImplementedStatement.php b/src/Statements/NotImplementedStatement.php
index b96c558..f5f8b8f 100644
--- a/src/Statements/NotImplementedStatement.php
+++ b/src/Statements/NotImplementedStatement.php
@@ -28,19 +28,40 @@ class NotImplementedStatement extends Statement
 {
 
     /**
-     * Function called after the token was processed.
-     *
-     * Jump to the end of the delimiter.
-     *
+     * The part of the statement that can't be parsed.
+     * @var Token[]
+     */
+    public $unknown = array();
+
+    /**
+     * @return string
+     */
+    public function build()
+    {
+        // Building the parsed part of the query (if any).
+        $query = parent::build() . ' ';
+
+        // Rebuilding the unknown part from tokens.
+        foreach ($this->unknown as $token) {
+            $query .= $token->token;
+        }
+
+        return $query;
+    }
+
+    /**
      * @param Parser     $parser The instance that requests parsing.
      * @param TokensList $list   The list of tokens to be parsed.
-     * @param Token      $token  The token that is being parsed.
      *
      * @return void
      */
-    public function after(Parser $parser, TokensList $list, Token $token)
+    public function parse(Parser $parser, TokensList $list)
     {
-        $list->getNextOfType(Token::TYPE_DELIMITER);
-        --$list->idx;
+        for (; $list->idx < $list->count; ++$list->idx) {
+            if ($list->tokens[$list->idx]->type === Token::TYPE_DELIMITER) {
+                break;
+            }
+            $this->unknown[] = $list->tokens[$list->idx];
+        }
     }
 }
diff --git a/src/Statements/SelectStatement.php b/src/Statements/SelectStatement.php
index 84ec5a2..e376b47 100644
--- a/src/Statements/SelectStatement.php
+++ b/src/Statements/SelectStatement.php
@@ -57,7 +57,7 @@ class SelectStatement extends Statement
         'DISTINCT'                      => 1,
         'DISTINCTROW'                   => 1,
         'HIGH_PRIORITY'                 => 2,
-        'MAX_STATEMENT_TIME'            => array(3, 'var'),
+        'MAX_STATEMENT_TIME'            => array(3, 'var='),
         'STRAIGHT_JOIN'                 => 4,
         'SQL_SMALL_RESULT'              => 5,
         'SQL_BIG_RESULT'                => 6,
diff --git a/src/TokensList.php b/src/TokensList.php
index 52a464e..229bebc 100644
--- a/src/TokensList.php
+++ b/src/TokensList.php
@@ -40,6 +40,42 @@ class TokensList implements \ArrayAccess
     public $idx = 0;
 
     /**
+     * Constructor.
+     *
+     * @param array $tokens The initial array of tokens.
+     */
+    public function __construct(array $tokens = array(), $count = -1)
+    {
+        if (!empty($tokens)) {
+            $this->tokens = $tokens;
+            if ($count === -1) {
+                $this->count = count($tokens);
+            }
+        }
+    }
+
+    /**
+     * Builds an array of tokens by merging their raw value.
+     *
+     * @param array $tokens
+     *
+     * @return string
+     */
+    public static function build($list)
+    {
+        if ($list instanceof TokensList) {
+            $list = $list->tokens;
+        }
+        $ret = '';
+        if (is_array($list)) {
+            foreach ($list as $tok) {
+                $ret .= $tok->token;
+            }
+        }
+        return $ret;
+    }
+
+    /**
      * Adds a new token.
      *
      * @param Token $token Token to be added in list.
@@ -61,7 +97,8 @@ class TokensList implements \ArrayAccess
     {
         for (; $this->idx < $this->count; ++$this->idx) {
             if (($this->tokens[$this->idx]->type !== Token::TYPE_WHITESPACE)
-                && ($this->tokens[$this->idx]->type !== Token::TYPE_COMMENT)) {
+                && ($this->tokens[$this->idx]->type !== Token::TYPE_COMMENT)
+            ) {
                 return $this->tokens[$this->idx++];
             }
         }
diff --git a/src/Utils/Query.php b/src/Utils/Query.php
index 11a08d0..f741620 100644
--- a/src/Utils/Query.php
+++ b/src/Utils/Query.php
@@ -531,7 +531,7 @@ class Query
 
         if ($onlyType) {
             return static::getClause($statement, $list, $old, -1, false) . ' ' .
-                $new . ' ' . static::getCLause($statement, $list, $old, 0) . ' ' .
+                $new . ' ' . static::getClause($statement, $list, $old, 0) . ' ' .
                 static::getClause($statement, $list, $old, 1, false);
         }
 
diff --git a/src/Utils/Table.php b/src/Utils/Table.php
index 86ccbfb..ba7f82f 100644
--- a/src/Utils/Table.php
+++ b/src/Utils/Table.php
@@ -36,7 +36,10 @@ class Table
      */
     public static function getForeignKeys($statement)
     {
-        if ((empty($statement->fields)) || (!$statement->options->has('TABLE'))) {
+        if ((empty($statement->fields))
+            || (!is_array($statement->fields))
+            || (!$statement->options->has('TABLE'))
+        ) {
             return array();
         }
 
@@ -85,7 +88,10 @@ class Table
      */
     public static function getFields($statement)
     {
-        if ((empty($statement->fields)) || (!$statement->options->has('TABLE'))) {
+        if ((empty($statement->fields))
+            || (!is_array($statement->fields))
+            || (!$statement->options->has('TABLE'))
+        ) {
             return array();
         }