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WHERE IN syntax for Exist/Not Exist
Message
De
29/01/2017 12:25:39
 
 
Information générale
Forum:
Microsoft SQL Server
Catégorie:
Syntaxe SQL
Versions des environnements
SQL Server:
SQL Server 2014
OS:
Windows 8.1
Network:
Windows Server 2012
Divers
Thread ID:
01647092
Message ID:
01647117
Vues:
28
>
>What I learned is that IN with a subquery is always very poor performance and should never be done. Always use Exists instead.
>
>http://stackoverflow.com/questions/2065329/sql-server-in-vs-exists-performance

Christian, that line about "always very poor performance" is simply not true.

Yes, there are benefits to using EXISTS - but for almost the last 10 years, the optimizer often will generate the same plan. If you'd read that full stackoverflow article (and many others out there), you'd see there can be several factors.
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