DELETE FROM task_queue
WHERE id = ( -- Use '=' for a single expected ID
SELECT id FROM task_queue
WHERE queue_group_id = 15
LIMIT 1
FOR UPDATE SKIP LOCKED
)
RETURNING item_id;
I don't understand where that item_id value comes from, since that's not a column that's mentioned anywhere else in the query.
I guess it must be an unmentioned column on that task_queue table?
In DELETE ... RETURNING, RETURNING works like SELECT in a read query, so, yes, item_id is a column in task_queue and the result set is the item_id value of the row deleted.
I guess it must be an unmentioned column on that task_queue table?