ISNULL behavior - SQL Server Forums

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ISNULL behavior

Author

Topic

WJHamel
Aged Yak Warrior

651 Posts

Posted - 2012-04-12 : 09:54:57

Will ISNULL treat an empty string the same as a null string?

sunitabeck
Master Smack Fu Yak Hacker

5155 Posts

Posted - 2012-04-12 : 10:11:06

No, it won't, as demonstrated by the example below:

DECLARE @x VARCHAR(32);
SET @x = '';
SELECT ISNULL(@x,'Aha! It is NULL');

If you do want it to be null, you can nest the NULLIF function:

DECLARE @x VARCHAR(32);
SET @x = '';
SELECT ISNULL(NULLIF(@x,''),'Aha! It is NULL');

Nullif will ignore trailing spaces:

DECLARE @x VARCHAR(32);
SET @x = '   '; --spaces
SELECT ISNULL(NULLIF(@x,''),'Aha! It is NULL');

WJHamel
Aged Yak Warrior

651 Posts

Posted - 2012-04-12 : 10:37:27

Wow. This is disturbing. I was given the exact opposite answer from the powers-that-be around me. i guess "question authority" still applies.

russell
Pyro-ma-ni-yak

5072 Posts

Posted - 2012-04-12 : 11:28:04

Or...Trust but verify.

WJHamel
Aged Yak Warrior

651 Posts

Posted - 2012-04-12 : 11:55:04

that's why i hang out here.

madhivanan
Premature Yak Congratulator

22864 Posts

Posted - 2012-04-17 : 04:34:14

In ORACLE emptry string is equal to NULL

Madhivanan

Failing to plan is Planning to fail

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