Avoid building a field multiple times if clause has synonyms.v3.0.3

1 files changed, 23 insertions, 0 deletions

diff --git a/src/Statement.php b/src/Statement.php
index 3fe3f42..b15dc3d 100644
--- a/src/Statement.php
+++ b/src/Statement.php
@@ -108,6 +108,20 @@ abstract class Statement
          */
         $query = '';
 
+        /**
+         * Clauses which were built already.
+         *
+         * It is required to keep track of built clauses because some fields,
+         * for example `join` is used by multiple clauses (`JOIN`, `LEFT JOIN`,
+         * `LEFT OUTER JOIN`, etc.). The same happens for `VALUE` and `VALUES`.
+         *
+         * A clause is considered built just after fields' value
+         * (`$this->field`) was used in building.
+         *
+         * @var array
+         */
+        $built = array();
+
         foreach (static::$CLAUSES as $clause) {
             /**
              * The name of the clause.
@@ -144,6 +158,15 @@ abstract class Statement
                 continue;
             }
 
+            // Checking if this field was already built.
+            if ($type & 1) {
+                if (!empty($built[$field])) {
+                    continue;
+                }
+
+                $built[$field] = true;
+            }
+
             // Checking if the name of the clause should be added.
             if ($type & 2) {
                 $query .= $name . ' ';