问题
I have an SSRS report which I want to sum values of a field, but only if the value of another field is equal to 1, as I have made the report output a row number for each row. Bascially, I'm trying to sum the distinct values to come up with a total. Screenshot below. I'm getting an error for orders with more than 1 item. My expression used to calculate the Ship Cost (red text) is as follows
=SUM(IIF(Fields!RowNumber.Value = 1, Fields!WEIGHT.Value, 0))
But I'm getting the #Error. The cell that has the text #Error should be reading $11.25.
回答1:
I think you're likely getting a datatype mismatch in the aggregate; SSRS can't handle implicit conversions in these sort of IIf/aggregate expressions.
In your expression, 0 will be treated as an int, and assuming the underlying data type of Fields!WEIGHT.Value is decimal or double, this will throw a runtime error - if you preview in BIDS it should actually display the error.
To get around this you need to make sure the two IIf results have the same datatype - something like:
=SUM(IIF(Fields!RowNumber.Value = 1, Fields!WEIGHT.Value, 0.0))
or
=SUM(IIF(Fields!RowNumber.Value = 1, Fields!WEIGHT.Value, CDec(0)))
or
=SUM(IIF(Fields!RowNumber.Value = 1, Fields!WEIGHT.Value, CDbl(0)))
Depending on the underlying datatype you may have to try a few combinations but hopefully one of the examples will work correctly,
回答2:
See here: http://www.bidn.com/forums/microsoft-business-intelligence/reporting-services/589/how-to-sum-at-group-level
If your group is called "Order#", your expression should be:=SUM(IIF(Fields!RowNumber.Value = 1, Fields!Weight.Value, 0),"Order#")
来源：https://stackoverflow.com/questions/18236373/expression-in-ssrs-not-working-as-expected