Fatal error: Uncaught mysqli_sql_exception: Duplicate entry 'heungmin' for key 'mem_id' in /users/2020/i2019055/public_html/WebDB/06/insert.php:17 Stack trace: #0 /users/2020/i2019055/public_html/WebDB/06/insert.php(17): mysqli_query() #1 {main} thrown in /users/2020/i2019055/public_html/WebDB/06/insert.php on line 17