Improving Expression to allow is null and is not null column options

Fixes: phpmyadmin/phpmyadmin#17422
Signed-off-by: iifawzi <[email protected]>

Author: iifawzi

CHANGELOG.md

@@ -13,7 +13,8 @@
 * Fixed differentiating between `ANALYZE` and `EXPLAIN` statements (#386)
 * Added "NOT" to the select options (#374)
 * Implement the `EXPLAIN` Parser (#389)
-* Context: Updated contexts to contain `multipoint` and `multipolygon` data types. (#393)
+* Context: Updated contexts to contain `multipoint` and `multipolygon` data types (#393)
+* Improving Expression to allow `IS NULL` and `IS NOT NULL` column options (#399)
 
 ## [5.5.0] - 2021-12-08
 

src/Components/Expression.php

@@ -13,6 +13,7 @@
 
 use function implode;
 use function is_array;
+use function rtrim;
 use function strlen;
 use function trim;
 
@@ -33,7 +34,6 @@ class Expression extends Component
     private static $ALLOWED_KEYWORDS = [
         'AS' => 1,
         'DUAL' => 1,
-        'NULL' => 1,
         'REGEXP' => 1,
         'CASE' => 1,
         'DIV' => 1,
@@ -44,6 +44,10 @@ class Expression extends Component
         'MOD' => 1,
 
         'OVER' => 2,
+
+        'IS' => 3,
+        'NOT NULL' => 4,
+        'NULL' => 4,
     ];
 
     /**
@@ -371,6 +375,20 @@ public static function parse(Parser $parser, TokensList $list, array $options =
 
                     $ret->alias = $prev[1]->value;
                 } else {
+                    $currIdx = $list->idx;
+                    --$list->idx;
+                    $beforeToken = $list->getPrevious();
+                    $list->idx = $currIdx;
+                    // columns names tokens are of type NONE, and the columns options
+                    // would start with a token of type KEYWORD, in that case, we want to have a space
+                    // between the tokens.
+                    if (
+                        $ret->expr !== null && $beforeToken &&
+                        $beforeToken->type === Token::TYPE_NONE && $token->type === Token::TYPE_KEYWORD
+                    ) {
+                        $ret->expr = rtrim($ret->expr, ' ') . ' ';
+                    }
+
                     $ret->expr .= $token->token;
                 }
             } elseif (! $isExpr) {

tests/Builder/SelectStatementTest.php

@@ -35,6 +35,19 @@ public function testBuilderUnion(): void
         );
     }
 
+    public function testBuilderWithIsNull(): void
+    {
+        $parser = new Parser('SELECT test3.t1 is not null AS `col1` FROM test3');
+        $stmt = $parser->statements[0];
+
+        $this->assertEquals('SELECT test3.t1 is not null AS `col1` FROM test3', $stmt->build());
+
+        $parser = new Parser('SELECT test3.t1 is null AS `col1` FROM test3');
+        $stmt = $parser->statements[0];
+
+        $this->assertEquals('SELECT test3.t1 is null AS `col1` FROM test3', $stmt->build());
+    }
+
     public function testBuilderAlias(): void
     {
         $parser = new Parser(

tests/data/parser/parseCreateView5.in

@@ -0,0 +1 @@
+CREATE VIEW `t3` as SELECT `t1` IS NOT NULL AS `is_not_null` FROM `test3`;