使用“UNION”删除MySQLI查询

Question

I want to delete some informations of my database in 2 tables.

First question, is it possible ? If yes:

I had tried a UNION DELETE query, but it doesn't work.

$delete = mysqli_query($sql, "(DELETE FROM table1 WHERE id LIKE '".$id."' && userid LIKE '".$userid."') UNION (DELETE FROM table2 WHERE source_id LIKE '".$id."' && userid LIKE '".$userid."')");

Answer 1

UNION is used only with SELECT statements:

http://dev.mysql.com/doc/refman/5.7/en/union.html

If you don't want to use two separate DELETE statements and those two tables are related, try using the JOIN statement:

https://dev.mysql.com/doc/refman/5.7/en/join.html