Comments on: MERGE syntax

By: Laurent Schneider

Laurent Schneider — Thu, 06 Sep 2007 08:05:54 +0000

exp/imp? or truncate than insert as select?

By: Hal Armstrong

Hal Armstrong — Wed, 05 Sep 2007 21:56:49 +0000

I have issues where I have several development databases and some are up to date and some are behind. Merge can be used to write scripts to “Force this data, whether by INSERT or UPDATE”.

Example:
MERGE INTO po_discount_reason dest
USING (SELECT 40 AS PO_DISCOUNT_REASON_CD FROM dual) sou
ON (sou.PO_DISCOUNT_REASON_CD = dest.PO_DISCOUNT_REASON_CD)
WHEN MATCHED THEN
UPDATE SET
rank = 40,
name = ‘Temporary Discount’,
description = ‘Temporary Discount’
WHEN NOT MATCHED THEN
INSERT (
po_discount_reason_cd, rank, name, description )
VALUES (
40, 40, ‘Temporary Discount’, ‘Temporary Discount’);

The above works. Is there any simpler way to do the same?

By: Laurent Schneider

Laurent Schneider — Tue, 15 May 2007 10:39:55 +0000

merge into t1 using t2 on (t1.id=t2.id)
when matched then
update set name=t2.name;

to update only the rows that have changed, I add a where clause


merge into t1 using t2 on (t1.id=t2.id)
when matched then
  update set name=t2.name
  where lnnvl(name=t2.name);

By: Laurent Schneider

Laurent Schneider — Mon, 14 May 2007 18:12:47 +0000

well, the can only delete when matched, I would be more interested in deleting <2;ORANGE> or betting updating <2;ORANGE> to <2;ORANGE;deleted> thanks for the comments

By: Jeff Moss

Jeff Moss — Mon, 14 May 2007 17:58:41 +0000

…can also do DELETE operations too…as I’m sure you’re aware Laurent.

http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_9016.htm#i2081030

By: vidya

vidya — Mon, 14 May 2007 16:58:55 +0000

Thanks Laurent …intuitive and extremely useful (both for db and ETL developers)