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Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in C:\xampp\htdocs\sub-review-section.php:10 Stack trace: #0 C:\xampp\htdocs\sub-review-section.php(10): mysqli_query(NULL, 'SELECT * FROM r...') #1 {main} thrown in C:\xampp\htdocs\sub-review-section.php on line 10