GilaMonster (10/31/2012)

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No, the Halloween problem is exclusively for updates. You can't insert or delete a row multiple times, you can an update and that's the problem. You may see spools in insert or delete plans, but they are not there for halloween protection.

DELETE  TABLE_NAME
WHERE   COL < CONST

DELETE  TABLE_NAME
WHERE   COL < (SELECT AVG(COL) FROM TABLE_NAME)

DELETE  TABLE_NAME
WHERE   COL1 NOT IN (SELECT COL2 FROM TABLE_NAME)

COL1  COL2
1     2
2     3
3     4

Nakul Vachhrajani (10/31/2012)

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Very nice question! With a little thought, I was certain about the answer. While this was the first time I heard about "halloween protection", the chain of thought I used was Halloween = ghosts & goblins. Ghosts = phantom. We all know about "phantom updates" and hence the answer had to be what it is.

GilaMonster (10/31/2012)

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No, the Halloween problem is exclusively for updates. You can't insert or delete a row multiple times, you can an update and that's the problem. You may see spools in insert or delete plans, but they are not there for halloween protection.

craig 81366 (10/31/2012)

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I beg to differ
...
that spool is essential to protecting against deleting more rows than expected

vk-kirov (10/31/2012)

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"Delete a row multiple times" and "Delete more rows than expected" – there is a big difference, I believe.

GilaMonster (10/31/2012)

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No, the Halloween problem is exclusively for updates. You can't insert or delete a row multiple times, you can an update and that's the problem. You may see spools in insert or delete plans, but they are not there for halloween protection.

vk-kirov (10/31/2012)

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"Delete a row multiple times" and "Delete more rows than expected" – there is a big difference, I believe.