You can specify multiple tables in a DELETE statement to delete rows from one or more tables depending on the particular condition in the WHERE clause. However, you cannot use ORDER BY or LIMIT in a multiple-table DELETE. The table_references clause lists the tables involved in the join. Its syntax is described in Section 188.8.131.52, JOIN Syntax.
For the first multiple-table syntax, only matching rows from the tables listed before the FROM clause are deleted. For the second multiple-table syntax, only matching rows from the tables listed in the FROM clause (before the USING clause) are deleted. The effect is that you can delete rows from many tables at the same time and have additional tables that are used only for searching:
DELETE t1, t2 FROM t1, t2, t3 WHERE t1.id=t2.id AND t2.id=t3.id;
DELETE FROM t1, t2 USING t1, t2, t3 WHERE t1.id=t2.id AND t2.id=t3.id;
These statements use all three tables when searching for rows to delete, but delete matching rows only from tables t1 and t2.
The preceding examples show inner joins that use the comma operator, but multiple-table DELETE statements can use any type of join allowed in SELECT statements, such as LEFT JOIN.
The syntax allows .* after the table names for compatibility with Access.
If you use a multiple-table DELETE statement involving InnoDB tables for which there are foreign key constraints, the MySQL optimizer might process tables in an order that differs from that of their parent/child relationship. In this case, the statement fails and rolls back. Instead, you should delete from a single table and rely on the ON DELETE capabilities that InnoDB provides to cause the other tables to be modified accordingly.
Note: If you provide an alias for a table, you must use the alias when referring to the table:
DELETE t1 FROM test AS t1, test2 WHERE ...
Cross-database deletes are supported for multiple-table deletes, but in this case, you must refer to the tables without using aliases. For example:
DELETE test1.tmp1, test2.tmp2 FROM test1.tmp1, test2.tmp2 WHERE ...
Currently, you cannot delete from a table and select from the same table in a subquery.