SUMIF/SUMIFS not working using Date fields as criteria

I have three columns "Billed Date", "Paid Date" and "Amount" and trying to use either SUMIF or SUMIFS function.

I tried using "is null" or "<> null" to sum values and must have the syntax wrong.

If I want to sum on those amounts with "Billed Date" not blank and "Paid Date" blank....

Thanks so much in advance!!

First of all, SUMIF and SUMIFS have two different syntax.

SUMIF (range, criteria, [sum_range]) whereas SUMIFS (sum_range, criteria_range1, criteria1, ..., ...)

In your example, I would use SUMIFS...and assuming that "Billed Date" is on column A and "Paid Date" is on column B, and "Amount" is on column C, and that you only have 10 rows of data (from row 2 to row 11), then the formula would be

=SUMIFS($C$2:$C$10, $A$2:$A$10, "<>", $B$2:$B$10, "=")