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#Error using IIF and divide by zero

I am getting an error in a calculated field that could potentially divide by zero, even though I'm using an IIF. The column displays in the report as "#Error". My expression looks like this:
= IIF(Fields!Qty.Value = 0, "None", Fields!Hours.Value / Fields!Qty.Value)
I have successfully used this approach with INT fields, but this time the Hours field is a NUMERIC(9,2). My workaround is to do this:
IIF(Fields!Qty.Value = 0, "None", IIF(Fields!Qty.Value = 0, 42, Fields!Hours.Value) / Fields!Qty.Value)
I guess the 42 is cast to an INT inside the second IIF and the calculation works.
What's strange is that the division would even be carried out in the event of Qty = 0 from the first IIF, because the expression should just evaluate to "None" and that would be that.
Has anybody run into this problem? Is my workaround the recommended approach?
Larry
Question
Answers

Hi Larry,
I recommend to add a custom code function for the division (in Report > Report Properties > Code):
Public Function Divide(ByVal first As Double, ByVal second As Double) As Double
If second = 0 Then
Return 0
Else
Return first / second
End If
End FunctionThen, modify the expression accordingly:
= IIF(Fields!Qty.Value = 0, "None", Code.Divide(Fields!Hours.Value, Fields!Qty.Value))
 Robert
All replies


Hi Larry,
I recommend to add a custom code function for the division (in Report > Report Properties > Code):
Public Function Divide(ByVal first As Double, ByVal second As Double) As Double
If second = 0 Then
Return 0
Else
Return first / second
End If
End FunctionThen, modify the expression accordingly:
= IIF(Fields!Qty.Value = 0, "None", Code.Divide(Fields!Hours.Value, Fields!Qty.Value))
 Robert

Thanks Robert, that's a good (dare I say) workaround. I'm still curious why the IIF errors out with the double division but works with integer division.
Also, the Edit Expression dialog has the "Divide" text underlined in red, but my project builds successfully and runs ok too. Any idea why it might think it's invalid?
Larry



hi Larry,
use this,it would work
=iif(Fields!Hours.Value = 0,0, Fields!NetSales.Value/Fields!Hours.Value)
amit
 Proposed as answer by Amit Srivastava Thursday, December 30, 2010 9:59 AM



I have noticed that the problem occurs only when dividing decimals.
When dividing integers it works properly.
So I tried using something like this:
=iif(a = 0, 0, CInt(b * 100) / CInt(a * 100))
Of course, for it to work, we need to decide how many decimal digits are significant and multiply by 10 to their power e.g. for 3 digits multiply by 10^3=1000).
Needless to say that the code solution offered Robert Bruckner is much more preferable, I just wanted to specialize the problem a bit more.
 Edited by sinadroi Tuesday, November 19, 2013 10:51 AM typo

This function works great, but if you have a calculated field you will get errors about aggregates, not sure how to get round this! Any ideas?
Thanks,
Kev
 Proposed as answer by turkeyhunter Wednesday, February 05, 2014 12:00 AM
 Unproposed as answer by turkeyhunter Wednesday, February 05, 2014 12:00 AM

First a diatribe: This is just one of the many annoying "features" of SSRS that needs to be fixed. It should just flat out work. Period.
Now the fix.
The following formula to calculate Discount% gives the #Error result if List = 0
=iif(Fields!List.Value=0,0, (Fields!List.ValueFields!Net.Value)/Fields!List.Value)
However, if you add a very small number to the divisor it will work.
=iif(Fields!List.Value=0,0, (Fields!List.ValueFields!Net.Value)/(Fields!List.Value+.000001))
Apparently SSRS evaluates the false part of the expression before it tests. Try this in most any other language and you will not have this problem.
You just need to add a small enough number to your formula to not impact your results when the divisor is not zero.
You can actually leave out the IIF entirely if you do this:
Fields!List.ValueFields!Net.Value)/(Fields!List.Value+.000001)
I usually leave the syntax in there just so I know what the intention was.
 Edited by turkeyhunter Wednesday, February 05, 2014 1:34 AM


Yes; IIF evaluates both sides of the equation, so upon further reading, you have to apply an IIF in 2 places as shown below:
=IIf(Fields!SomeField.Value = 0, 0, Fields!SomeOtherField.Value / IIf(Fields!SomeField.Value = 0, 1, Fields!SomeField.Value))

SSRS is confusing the types I calculated fields try: Similar to using float in sql 0 is not zero but an approximation close to zero
=iif(
round(sum(Fields!Qty.Value),2) = 0.00 ,
0.00,
round(
sum(Fields!FirstQty.Value) * 1.00
/
sum(Fields!Qty.Value) * 1.00
,2
)
)