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Output of Query


Output of Query

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SQLRNNR
SQLRNNR
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Thanks for the question.



Jason AKA CirqueDeSQLeil
I have given a name to my pain...
MCM SQL Server, MVP


SQL RNNR

Posting Performance Based Questions - Gail Shaw

Sherwin Anderson
Sherwin Anderson
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Good question, luckily read the question twice before answering.
Aaron N. Cutshall
Aaron N. Cutshall
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Bugger! I hate it when I know the right answer but click on the wrong choice! Angry


"...when ye are in the service of your fellow beings ye are only in the service of your God." -- Mosiah 2:17
Revenant
Revenant
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Simple but neat -- thank you!
Ken Wymore
Ken Wymore
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Nice question about something that comes up regularly for me. Especially in writing queries for reporting.
James_B
James_B
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Great question - unfortunately I got it wrong.

I thought it was too simple so I over compensated and assumed that the code would have "set ansi_nulls off" for the session since it is effectively saying "where col1 = null" rather than "where col1 is null".
OzYbOi d(-_-)b
OzYbOi d(-_-)b
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good question - tks
john.moreno
john.moreno
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I'd like to suggest a modification of the answer. What is happening is that the "CASE COLUMN WHEN" syntax does an equity comparision and then uses the result of that comparision, which of course fails with NULL, while the "CASE WHEN x" syntax uses the result of x. Which is why the given query returns null.

So, something like:

The CASE's statement has two alternative syntaxs, "CASE ColumnName WHEN Value" does an equity comparision between the column and the given value. This fails with NULLS unless ANSI_NULLS is off. The other syntax is "CASE WHEN EXPRESSION", which evalutes an expression (which may use any available columns) and uses the result of that expression to determine whether the condition has been met and the associated THEN used.
Evil Kraig F
Evil Kraig F
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Thanks for the question. It was a good caffination check this morning. :-)


- Craig Farrell

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Rob Schripsema
Rob Schripsema
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Excellent question. Thanks!

Rob Schripsema
Propack, Inc.
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