Hello, 

I am trying to write a crystal report formula that does the following:

If an amended PO number exists in the UDF_AMENDED_PO field, then return UDF_AMENDED_PO, if not, return CustomerPONo

When I test this, when UDF_PO_NO is NULL, it returns blank instead of returning CustomerPONo. Can anyone see any reason why this isn't working as expected?

(I have tried writing an if-then-else function which yielded the same results).

There are no syntax issues here:

IIF (IsNull({AR_InvoiceHistoryHeader.UDF_PO_AMENDED}),{SO_InvoiceWrk.CustomerPONo},{AR_InvoiceHistoryHeader.UDF_PO_AMENDED})