Re: [PERFORM] Are JOINs allowed with DELETE FROM

[John Arbash Meinel]

Gaetano Mendola wrote:

Steven Rosenstein wrote:

DELETE FROM detail JOIN summary ON (summary.id=detail.sum_id) WHERE
collect_date='2005-02-05';

You have to tell it what table you are deleting from. Select * from A
join B is both tables. What you want to do is fix the where clause.

DELETE FROM detail WHERE detail.sum_id in ( select id from summary  )
AND collect_date='2005-02-05';

I'm guessing this should actually be
DELETE FROM detail WHERE detail.sum_id in ( SELECT id FROM summary WHERE
collect_date='2005-02-05' );
Otherwise you wouldn't really need the join.

You have to come up with a plan that yields rows that are in the table
you want to delete. The rows that result from
select * from detail join summary, contain values from both tables.

If you want to delete from both tables, I think this has to be 2
deletes. Probably best to be in a transaction.

BEGIN;
DELETE FROM detail WHERE ...
DELETE FROM summary WHERE collect_date = '2005-02-05';
COMMIT;

Regards
Gaetano Mendola

John
=:->

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