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Warning: Undefined array key "hopdong_ma" in C:\xampp\htdocs\PEC\HopDong\list_hd_da_them.php on line 8

Fatal error: Uncaught mysqli_sql_exception: Unknown column 'tbl_hopdong.HopDong_ma' in 'where clause' in C:\xampp\htdocs\PEC\HopDong\list_hd_da_them.php:18 Stack trace: #0 C:\xampp\htdocs\PEC\HopDong\list_hd_da_them.php(18): mysqli->query('SELECT tbl_tram...') #1 {main} thrown in C:\xampp\htdocs\PEC\HopDong\list_hd_da_them.php on line 18