Counting Unique Entries (Dates, specifically)

[SJSkilbred]

Hello,
I'm looking to count the number of unique dates in a given range, using an equation that combines the two below:

=SUM(IF(FREQUENCY(D3:D15,D3:D15)>0,1))

This equation gives me the count of unique entries (dates) in the range of selected cells.

Since this is a huge spreadsheet that would be very time consuming to set a range for every single entry, I'm trying replace the existing range in red with a technique similar to this sum equation:

=SUMIFS(G:G,F:F,F3)

where the sum of another set of data is filtered by the criteria in an adjacent cell in row F.

I would appreciate any help.

Thanks
Stephen