2 files changed, 2 insertions, 2 deletions
diff --git a/src/Components/Expression.php b/src/Components/Expression.php
index 108f335..2c22241 100644
--- a/src/Components/Expression.php
+++ b/src/Components/Expression.php
@@ -436,7 +436,7 @@ class Expression extends Component
             return implode(', ', $component);
         }
 
-        if ($component->expr !== '' && ! is_null($component->expr)) {
+        if ($component->expr !== '' && $component->expr !== null) {
             $ret = $component->expr;
         } else {
             $fields = [];
diff --git a/src/Components/SetOperation.php b/src/Components/SetOperation.php
index 2d76704..eef0f80 100644
--- a/src/Components/SetOperation.php
+++ b/src/Components/SetOperation.php
@@ -122,7 +122,7 @@ class SetOperation extends Component
                         'breakOnAlias' => true,
                     ]
                 );
-                if (is_null($tmp)) {
+                if ($tmp === null) {
                     $parser->error('Missing expression.', $token);
                     break;
                 }