Converting "not in" to "not exists"

Question

Converting "not in" to "not exists"

aiki4ever-796329

SSC Veteran

Points: 251
More actions
June 27, 2013 at 8:58 am

#274497

/* I'm trying to change "not in" to "not exists" and I don't have the syntax quite right. The first statement updates multiple rows
while the second statement updates 0 rows. This is for SQL Server. */
update VehicleWorld set EstimatedDeletedDate=1
where Vehicle_ID not in (select Vehicle_ID from CFS_Production..CORE_VehicleAdSearch ads)
update VehicleWorld set EstimatedDeletedDate=1
where not exists
(select 1 from VehicleWorld car, CFS_Production..CORE_VehicleAdSearch ads
where car.Vehicle_ID = ads.Vehicle_ID)

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Lowell SSC Guru Points: 323504 More actions · Answer 1

i prefer to use aliases for my updates, because the format for SQL makes it easy to include a SELECT statement very easily, which lets me do a quick Sanity Check by running the SELECT portion with the identical criteria.

how does this work for you?

UPDATE MyTarget

SET MyTarget.EstimatedDeletedDate = 1

--highlight and execute starting at the SELECT

--SELECT MyTarget.EstimatedDeletedDate,*

FROM VehicleWorld MyTarget

WHERE NOT EXISTS

(SELECT 1 FROM VCFS_Production..CORE_VehicleAdSearch ads

WHERE MyTarget.Vehicle_ID = ads.Vehicle_ID)

AND MyTarget.EstimatedDeletedDate <> 1

Lowell

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Ed Wagner SSC Guru Points: 287024 More actions · Answer 2

aiki4ever-796329 (6/27/2013)
/* I'm trying to change "not in" to "not exists" and I don't have the syntax quite right. The first statement updates multiple rows
while the second statement updates 0 rows. This is for SQL Server. */
update VehicleWorld set EstimatedDeletedDate=1
where Vehicle_ID not in (select Vehicle_ID from CFS_Production..CORE_VehicleAdSearch ads)
update VehicleWorld set EstimatedDeletedDate=1
where not exists
(select 1 from VehicleWorld car, CFS_Production..CORE_VehicleAdSearch ads
where car.Vehicle_ID = ads.Vehicle_ID)

One important point here is that you're selecting from VehicleWorld in the subquery and then joining your table you check to it. This means that it won't join to the outer VehicleWorld table, so your update won't work. The one below should do the update because the subquery is correlated to the outer table.

update VehicleWorld

set EstimatedDeletedDate = 1

where not exists (select 1

from CFS_Production..CORE_VehicleAdSearch ads

where VehicleWorld.Vehicle_ID = ads.Vehicle_ID);

All that being said, I completely agree with Lowell...the syntax that allows you to select before firing an update is a good safety measure to make sure you aren't surprised by firing the update.

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aiki4ever-796329 SSC Veteran Points: 251 More actions · Answer 3

I see my problem. I had two tables in my subquery instead of one. That syntax is certainly confusing. Thank you gentlemen for your kind assistance. I'm quite glad that there are people in the world who understand SQL better than I do and who are willing to spread their knowledge. 🙂