SQL Queries - Delete, Insert & Trigger

Delete from multi table - Interconnect:

DELETE a.*, b.*, qz.* FROM tbl_question a LEFT JOIN tbl_answer b ON b.question_id = a.id LEFT JOIN tbl_question_quiz as qz ON qz.question_id=a.id WHERE a.id = 13 and qz.quiz_id=15

Insert Answer in 'tbl_answer' table:

INSERT INTO tbl_answer (question_id, title, is_correct) SELECT '32' AS question_id,title,is_correct FROM tbl_answer WHERE question_id=1

Trigger:

$trigger_chk = mysql_query('SELECT COUNT(*) as chk_row FROM information_schema.triggers WHERE trigger_name="before1_quiz_delete";',$j4g_db);   $t_chk = @mysql_fetch_assoc($trigger_chk);   if ($t_chk['chk_row'] == 0) {     $trigger_query = "     CREATE TRIGGER `before_quiz_delete` BEFORE DELETE ON `tbl_quiz` FOR EACH ROW     DELETE qq, q, qu, a FROM tbl_question_quiz AS qq     LEFT JOIN tbl_question AS q ON q.id=qq.question_id     LEFT JOIN tbl_answer AS a ON a.question_id=qq.question_id     LEFT JOIN tbl_quiz_user AS qu ON qu.quiz_id = qq.quiz_id     WHERE qq.quiz_id = OLD.id;";       mysql_query($trigger_query,$j4g_db); }