Fatal error: Uncaught mysqli_sql_exception: Duplicate column name 'markers_addresses' in C:\Apache24\htdocs\update\update_4.php:25 Stack trace: #0 C:\Apache24\htdocs\update\update_4.php(25): mysqli_query(Object(mysqli), 'alter table gs_...') #1 {main} thrown in C:\Apache24\htdocs\update\update_4.php on line 25