ricardo ricardo - 3 months ago 7
MySQL Question

Update a column in MySQL table if only the values are empty or NULL

I had previously applied this query...which works perfectly and was answered by one of the fellow members of this forum

UPDATE
jos_jbjobs_jobseeker a
INNER JOIN jos_users b ON a.email = b.email
SET
a.user_id = b.id


Now i want to use the same query adding one more condition... i.e

Set a.user_id = b.id only if a.user_id is empty ,,

can i apply this :


if a.user_id = '' SET a.user_id = b.id ;


?

Answer
UPDATE
    jos_jbjobs_jobseeker a
    INNER JOIN jos_users b ON a.email = b.email
SET
    a.user_id = b.id
WHERE a.id IS NULL OR LENGTH(a.id)=0;