Counting unique combinations within dates

[collo]

[TABLE="width: 500"]
<tbody>[TR]
[TD]Public
[/TD]
[TD]1[/TD]
[TD]2017[/TD]
[/TR]
[TR]
[TD]Public[/TD]
[TD]2[/TD]
[TD]2018[/TD]
[/TR]
[TR]
[TD]Private[/TD]
[TD]3[/TD]
[TD]2017[/TD]
[/TR]
[TR]
[TD]Private[/TD]
[TD]3[/TD]
[TD]2018[/TD]
[/TR]
[TR]
[TD]Private[/TD]
[TD]4[/TD]
[TD]2018[/TD]
[/TR]
</tbody>[/TABLE]

So I'm trying to count the number of unique combinations of the first two columns, then according to the date.

I currently have:
{=SUM(--(FREQUENCY(IF($A:$A="Public",MATCH($B:$B,$B:$B,0)),ROW($B:$B)-ROW($B$1)+1)>0))}

Which will count the number of unique combinations, however I don't know how to incorporate the date parameter into this.
Possibly using SUMPRODUCT?
Something along the lines of:
{=SUMPRODUCT(--(FREQUENCY(IF($A:$A=$E11,MATCH($B:$B,$B:$B,0)),ROW($B:$B)-ROW($B$2)+1)>0)*(C:C=2018))}
It just comes out as #VALUE

Thanks in advance

 

[Gerald Higgins]

What exactly should the results be ?

 

[AhoyNC]

Maybe this array formula (enter with CTFL-SHIFT-ENTER):

=SUM(--(FREQUENCY(IF($A:$A="Public",IF($C:$C=2018,MATCH($B:$B,$B:$B,0))),ROW($B:$B)-ROW($B$1)+1)>0))

 

[collo]

That's perfect, simple as that!
Thanks!

 

[collo]

Just a little extra since it's actually a date range I'm dealing with, not just a year.

Is there a good way to place an AND in the IF where the - $C:$C=2018 - is?
Can't seem to get it to work.

Thanks again

 

[Nishant94]

Try this:

=SUM(--(FREQUENCY(IF(A:A="Public",IF(YEAR(C:C)=2018,MATCH(B:B,B:B,0))),ROW(B:B)-ROW($B$1)+1)>0))

 

[collo]

Apologies, I didn't explain that very well.

It needs to be within the tax year so needs two include results in a range between two dates.
FIX:
I've amended the original data to fit to a yearly basis, so yes the YEAR(C:C) works now.

If there is a better way to do it feel free.

Thanks