Question

I have table called scheduler. It contains following columns:

ID
sequence_id
schedule_time (timestamp)
processed
source_order

I need to delete duplicate rows from the table but keeping 1 row which has same schedule_time and source_order for a particular sequence_id where processed=0

Answer 1

DELETE yourTable FROM yourTable LEFT OUTER JOIN (
SELECT MIN(ID) AS minID FROM yourTable WHERE processed = 0 GROUP BY schedule_time, source_order
) AS keepRowTable ON yourTable.ID = keepRowTable.minID
WHERE keepRowTable.ID IS NULL AND processed = 0

I apply from this post ;P How can I remove duplicate rows?
Have you seen it?

–fixed version–

DELETE yourTable FROM yourTable LEFT OUTER JOIN (
SELECT MIN(ID) AS minID FROM yourTable WHERE processed = 0 GROUP BY schedule_time, source_order
) AS keepRowTable ON yourTable.ID = keepRowTable.minID
WHERE keepRowTable.minID IS NULL AND processed = 0