Question

I am trying this update statement using a case in MySQL, but It does not change any values.

The query does not give any errors, but there are 0 affected rows.

UPDATE `tablename`
SET `type` = (
    CASE
        WHEN `type` = 1 THEN 1
        WHEN `type` = 2 THEN 2
        WHEN `type` = 3 THEN 19
        WHEN `type` = 4 THEN null
        WHEN `type` = 5 THEN null
        WHEN `type` = 6 THEN 81
        WHEN `type` = 7 THEN null
        WHEN `type` = 8 THEN 22
        WHEN `type` = 9 THEN 21
        WHEN `type` = 10 THEN 78
        WHEN `type` = 11 THEN 80
        WHEN `type` = 12 THEN 79
    END)
WHERE user_id IS NOT NULL;

Anyone know how I can fix this.

Answer 1

Try moving type after the Case.

UPDATE `tablename`
SET `type` = 
    CASE `type`
        WHEN  1 THEN 1
        WHEN  2 THEN 2
        WHEN  3 THEN 19
        WHEN  4 THEN null
        WHEN  5 THEN null
        WHEN  6 THEN 81
        WHEN  7 THEN null
        WHEN  8 THEN 22
        WHEN  9 THEN 21
        WHEN  10 THEN 78
        WHEN  11 THEN 80
        WHEN  12 THEN 79
    END
WHERE user_id IS NOT NULL;