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Iif syntax

Author

Topic

sportsguy
Starting Member

39 Posts

Posted - 2013-01-23 : 20:44:14

Query is giving an error at IIF
I am not sure of the syntax for IIF evaluating a Null field.

What is the correct context for the evaluation part??
Neither of these work. . .


IIf(hdr.CONTRACT_NUMBER = Null, Null,IsNull(hdr.CONTRACT_NUMBER_MODIFIER,'Null')) AS "MODIFIER"

IIf(hdr.CONTRACT_NUMBER Is Null, Null,IsNull(hdr.CONTRACT_NUMBER_MODIFIER,'Null')) AS "MODIFIER"

thanks,

sportsguy

MS Access 20 years, SQL hack

sportsguy
Starting Member

39 Posts

Posted - 2013-01-23 : 21:06:09

I know this works, so as to not think i am a total SQL idiot


CASE WHEN hdr.CONTRACT_NUMBER Is Null THEN Null ELSE IsNull(hdr.CONTRACT_NUMBER_MODIFIER,'Null') END AS "MODIFIER"

sportsguy

MS Access 20 years, SQL hack

khtan
In (Som, Ni, Yak)

17689 Posts

Posted - 2013-01-23 : 21:20:34

What is the error message ?

i don't have SQL 2012 to confirm but according to the BOL, the true or false part should be a VALUE, meaning you can' have an expression like IsNull(hdr.CONTRACT_NUMBER_MODIFIER,'Null')

http://msdn.microsoft.com/en-us/library/hh213574.aspx

quote:


Syntax


IIF ( boolean_expression, true_value, false_value )

Arguments

boolean_expression

    A valid Boolean expression.

    If this argument is not a Boolean expression, then a syntax error is raised.
true_value

    Value to return if boolean_expression evaluates to true.
false_value

    Value to return if boolean_expression evaluates to false.

KH
[spoiler]Time is always against us[/spoiler]

sportsguy
Starting Member

39 Posts

Posted - 2013-01-24 : 12:06:52

Doesn't IS Null return a boolean expression, True or False?
In the Case Statement, IS Null returns a Boolean answer, NO??

I am OK with the CASE, was just trying to use this as a quicker shortcut. . .

MS Access 20 years, SQL hack

Lamprey
Master Smack Fu Yak Hacker

4614 Posts

Posted - 2013-01-24 : 12:10:33

quote:
Originally posted by sportsguy

Doesn't IS Null return a boolean expression, True or False?
In the Case Statement, IS Null returns a Boolean answer, NO??

I am OK with the CASE, was just trying to use this as a quicker shortcut. . .

MS Access 20 years, SQL hack

No, ISNULL is a very poorly named fucntion. It takes two parameters and returns teh first non-null value (or null if they are both null). There are debates as to which funciton is better to use, but I'd suggest using COALESCE instead of ISNULL. They do, basically, the same thing. However, COALESCE is ANSI compliant and it accepts N-number of paramters (instead of jsut two).

EDIT: Nenver mind. I read your questuion as about ISNULL not about the IS NULL operator..

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2013-01-25 : 01:24:29

quote:
Originally posted by sportsguy

Doesn't IS Null return a boolean expression, True or False?
In the Case Statement, IS Null returns a Boolean answer, NO??

I am OK with the CASE, was just trying to use this as a quicker shortcut. . .

MS Access 20 years, SQL hack

the IIF for your requirement is second one

IIf(hdr.CONTRACT_NUMBER Is Null, Null,IsNull(hdr.CONTRACT_NUMBER_MODIFIER,'Null')) AS "MODIFIER"

=NULL wont work under default conditions as NULL is not stored as a value and cant be used with operators like =,>,< etc

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/

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