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Not Exists


Not Exists

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ramana3327
ramana3327
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Hi,

I am working with a query. I am looking for an alternative to not exists. Is the exception works instead of not exists

set @studentID = (select stdentID from student where classID = @classID and registeredNumber = @RegisteredNumber);



DELETE TableB WHERE studentID = @studentID


IF NOT EXISTS (SELECT 1 FROM @TableB)

BEGIN
--Moving data from staging tables to main tables when @TableB data is not passed.

INSERT INTO TableB (...)
select (...) from Staging
where studentid= @studentid
else
begin
insert into tableB (..)
select (..)
from TableC
GilaMonster
GilaMonster
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Why are you looking for an alternative to NOT EXISTS?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass


Jeff Moden
Jeff Moden
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I second Gail's question. Why are you looking to replace WHERE NOT EXISTS? Unless there's a performance or resource usage problem with it (which might just need a bit of tweaking), I'd leave it alone.

--Jeff Moden

RBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
If you think its expensive to hire a professional to do the job, wait until you hire an amateur. -- Red Adair

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ramana3327
ramana3327
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I heard that for large table we can't use exist or not-exit will be problem.
GilaMonster
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ramana3327 (6/1/2014)
I heard that for large table we can't use exist or not-exit will be problem.


And you tested that statement and confirmed it to be true?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass


ramana3327
ramana3327
SSCrazy
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Actually I am getting some syntax error while executing that, so in the mean while I posted here to find any alternative.
GilaMonster
GilaMonster
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First test and see if there's a gram of truth in that statement and whether you even need to be looking for an alternative.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass


ChrisM@Work
ChrisM@Work
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ramana3327 (6/1/2014)
Actually I am getting some syntax error while executing that, so in the mean while I posted here to find any alternative.


ramana3327 (5/31/2014)

DELETE TableB WHERE studentID = @studentID

IF NOT EXISTS (SELECT 1 FROM @TableB)


Does @TableB exist or should you be referencing TableB? What's the error message?

“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden
Exploring Recursive CTEs by Example Dwain Camps
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