SSRS trouble using DateDiff in a IIF statement

问题

SSRS returns an #error when the statement is False, but No Start Date when the statement is True. I tested and the DateDiff is correct in the False side of the statement. I'm not sure which direction to go from here. Thank you.

=IIF(Fields!JobOrderIssueDate.Value = "", "No Start Date",DateDiff("d",Today(),Fields!ProjectedConstEndDate.Value))

回答1:

You are mixing data types in your IIF returning either a STRING or a DATE depending on the condition of the IIF. This is not going to work.

One approach would be to convert the data type returned by the FALSE condition so that it is also returns a STRING (using CStr()):

=IIF(Fields!JobOrderIssueDate.Value = "", "No Start Date",CStr( DateDiff("d",Today(),Fields!ProjectedConstEndDate.Value)))

or you could gain a little more control over formatting (using FormatDateTime()):

=IIF(Fields!JobOrderIssueDate.Value = "", "No Start Date",FormatDateTime( DateDiff("d",Today(),Fields!ProjectedConstEndDate.Value), DateFormat.ShortDate)) 

回答2:

Change format to compare between data and string also will not work, the best method to inspect the Date field with IsDate function

=IIF(IsDate(Fields!JobOrderIssueDate.Value), DateDiff("d",Today(),Fields!ProjectedConstEndDate.Value), "No Start Date")

来源：https://stackoverflow.com/questions/34276247/ssrs-trouble-using-datediff-in-a-iif-statement