Question

This has me stumped.

MySQL

UPDATE sets SET sets.current_count = (SELECT COUNT(leads_auto.set_id) AS current_count FROM leads_auto WHERE leads_auto.set_id =  (SELECT sets.set_id AS setID FROM sets WHERE sets.on_off = 0)) WHERE sets.on_off = 0

Seems right doesn’t it? Update the record current_count with the total number of rows in leads_auto which have the set_id value of the set_id of the sets table where the value of its on_off column is 0.

yet I get this error

#1093 - You can't specify target table 'sets' for update in FROM clause

I looked around and someone mentioned that it has to do with the operation being cyclic?

Answer 1

Create a temporary table for the result of SET

UPDATE sets
SET sets.current_count = 
                (
                SELECT COUNT(leads_auto.set_id) AS current_count
                FROM leads_auto
                WHERE leads_auto.set_id = 
                                (
                                    SELECT set_id
                                    FROM
                                    (
                                        SELECT sets.set_id AS setID
                                        FROM sets
                                        WHERE sets.on_off = 0
                                    ) c
                                )
                )
WHERE sets.on_off = 0