MySQL: Fix REGEXP and RLIKE parsing when pattern is NULL

src/parser/mod.rs

@@ -4222,9 +4222,8 @@ impl<'a> Parser<'a> {
                     self.prev_token();
                     let negated = self.parse_keyword(Keyword::NOT);
                     let regexp = self.parse_keyword(Keyword::REGEXP);
-                    let rlike = self.parse_keyword(Keyword::RLIKE);
-                    let null = if !self.in_column_definition_state() {
-                        self.parse_keyword(Keyword::NULL)
+                    let rlike = if !regexp {
+                        self.parse_keyword(Keyword::RLIKE)
                     } else {
                         false
                     };
@@ -4237,7 +4236,10 @@ impl<'a> Parser<'a> {
                             ),
                             regexp,
                         })
-                    } else if negated && null {
+                    } else if negated
+                        && !self.in_column_definition_state()
+                        && self.parse_keyword(Keyword::NULL)
+                    {
                         Ok(Expr::IsNotNull(Box::new(expr)))
                     } else if self.parse_keyword(Keyword::IN) {
                         self.parse_in(expr, negated, false)

tests/sqlparser_mysql.rs

@@ -3491,9 +3491,24 @@ fn parse_rlike_and_regexp() {
         "SELECT 1 WHERE 'a' REGEXP '^a$'",
         "SELECT 1 WHERE 'a' NOT RLIKE '^a$'",
         "SELECT 1 WHERE 'a' NOT REGEXP '^a$'",
+        "SELECT 'abc' REGEXP NULL",
+        "SELECT a RLIKE NULL FROM t",
+        "SELECT a NOT REGEXP NULL OR b FROM t",
+        "SELECT a NOT RLIKE NULL FROM t",
     ] {
         mysql_and_generic().verified_only_select(s);
     }
+
+    let select = mysql().verified_only_select("SELECT 'abc' REGEXP NULL");
+    assert_matches!(
+        &select.projection[0],
+        SelectItem::UnnamedExpr(Expr::RLike {
+            negated: false,
+            regexp: true,
+            pattern,
+            ..
+        }) if matches!(**pattern, Expr::Value(ValueWithSpan { value: Value::Null, .. }))
+    );
 }
 
 #[test]