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Groups > comp.databases.ms-sqlserver > #1841
| From | Erland Sommarskog <esquel@sommarskog.se> |
|---|---|
| Newsgroups | comp.databases.ms-sqlserver |
| Subject | Re: CASE issue |
| Date | 2014-11-24 11:26 +0000 |
| Organization | Erland Sommarskog |
| Message-ID | <XnsA3EF7E8B63B6CYazorman@127.0.0.1> (permalink) |
| References | <547306f8$0$41749$c3e8da3$5d8fb80f@news.astraweb.com> |
twenty-six@b-mint.net (twenty-six@b-mint.net) writes:
> When I run this query I get lots of 'Unknown' values, but I'm not sure
> why.
This happens because
CASE expr WHEN val1 THEN ....
WHEN val2 THEN ....
is a shortcut for
CASE WHEN expr = val1 THEN
WHEN expr = val2 THEN
and thus the expression gets evaluated multiple times and then it goes
downhill from there.
Set up a mapping table instead.
--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
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CASE issue "twenty-six@b-mint.net" <twenty-six@b-mint.net> - 2014-11-24 10:22 +0000
Re: CASE issue Erland Sommarskog <esquel@sommarskog.se> - 2014-11-24 11:26 +0000
Re: CASE issue bradbury9 <ray.bradbury9@gmail.com> - 2014-11-24 04:16 -0800
Re: CASE issue Erland Sommarskog <esquel@sommarskog.se> - 2014-11-24 14:28 +0000
Re: CASE issue Erland Sommarskog <esquel@sommarskog.se> - 2014-11-28 22:47 +0100
Re: CASE issue Jim <jgeissman@socal.rr.com> - 2014-11-28 17:19 -0800
Re: CASE issue "twenty-six@b-mint.net" <twenty-six@b-mint.net> - 2014-11-24 13:32 +0000
Re: CASE issue Erland Sommarskog <esquel@sommarskog.se> - 2014-11-24 14:25 +0000
Re: CASE issue "twenty-six@b-mint.net" <twenty-six@b-mint.net> - 2014-11-24 16:06 +0000
Re: CASE issue Lennart Jonsson <erik.lennart.jonsson@gmail.com> - 2014-11-24 17:18 +0100
Re: CASE issue Erland Sommarskog <esquel@sommarskog.se> - 2014-11-24 23:37 +0100
Re: CASE issue Lennart Jonsson <erik.lennart.jonsson@gmail.com> - 2014-11-25 06:25 +0100
Re: CASE issue Jim <jgeissman@socal.rr.com> - 2014-11-28 16:07 -0800
Re: CASE issue Erland Sommarskog <esquel@sommarskog.se> - 2014-11-29 10:43 +0100
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