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Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1 in C:\xampp\htdocs\API\liked.php:19 Stack trace: #0 C:\xampp\htdocs\API\liked.php(19): mysqli_query(Object(mysqli), 'SELECT post_id ...') #1 {main} thrown in C:\xampp\htdocs\API\liked.php on line 19