Question

Below query gives me “#1093 – You can’t specify target table ‘reservation_seats’ for update in FROM clause” error.

DELETE 
FROM reservation_seats 
WHERE id IN ( SELECT id 
              FROM reservation_seats 
              WHERE reservation_id NOT IN ( SELECT id FROM reservation)
            );

Table Structure :

reservation_seats - id,reservation_id,seat_no
reservation       - id,txn_id,name......
reservation table(id) column is used as the foreign in the reservation_seats table.
(reservation.id = reservation_seats.reservation_id )

Can you please tell me why is that and how to fix it?

Thanks

Answer 1

In MySQL you can’t delete from the table you are selecting from. Try

DELETE FROM reservation_seats
WHERE id IN ( 
              select * from 
              (
                   SELECT id FROM reservation_seats
                   WHERE reservation_id NOT IN ( SELECT id FROM reservation)
              )
);

to trick MySQL to do it anyway. BTW this could be made simpler like this

DELETE FROM reservation_seats
WHERE reservation_id NOT IN ( SELECT id FROM reservation)