Count values in column ignoring duplicates - excel

Question

Not really an Excel user, but what seemed simple has turned out to be very difficult for me. I am in trouble as I can't come up with a nice and clean (or any) way to get it working.
What I have here:
I need to create a new columnn that would tell the amount of employees in each occupation while ignoring the duplicates (highlighted).
The amount of names formula is working, so maybe this can be used ? Or maybe it's just in the way and should be cleared.
It's just:
=COUNTIFS(A:A;A2)
Tried searching for quite a while did not find anything suitable. Any help or advice would be much appreciated. I hope I explained it in clear manner.
Thank you

Answer 1

Without helper columns:
Two options, D2:
{=SUM(--(FREQUENCY(IF($B$2:$B$9=C2,MATCH($A$2:$A$9,$A$2:$A$9,0)),ROW($A$2:$A$9)-ROW($D$1)+1)>0))}
Or put in E2:
{=SUMPRODUCT((($B$2:$B$9=C2))/COUNTIFS($B$2:$B$9,$B$2:$B$9&"",$A$2:$A$9,$A$2:$A$9&""))}
Notice both are array formulas and should be entered through CtrlShiftEnter

Answer 2

SUMPRODUCT 'Deals' in Arrays 3
You might have employees with the same name (David, Michael) in different occupations (Tech & Worker, Tech & Economy). To distinguish those from each other, in B2 you can use:
=SUMPRODUCT((A$2:A$21=A2)*(C$2:C$21=C2))
In D2 you can use:
=SUMPRODUCT((1/B$2:B$21)*(C$2:C$21=C2))

Answer 3

Distinct Employees Occupation Count
with a helper column
Unique and Distinct values are tricky. Using a helper column is beneficial for identifying either one of these when coupled with an expanding range:
=SUMPRODUCT((A2=$A$1:$A1)*(C2=$C$1:$C1))
Relative Rows: ^ ^
Paste to cell E2.
Copy Drag the formula down from the where pasted.
The relative row numbers identified above well increase as the formula is copy dragged down. This creates a larger and larger range for comparison. An expanding range.
In this case the range that is expanding is the range of already checked values. Many times the result range is expanded and tested against to eliminate posting duplicates of already posted results in subsequent rows of the results list.
The helper column's value is how many times the name and occupation pair has previously appeared. Zero previous appearances tells us this is the first occurance. We will only count the zeros (first occurance) in the main formula.
The main formula for counting distinct employees in each occupation:
=COUNTIFS( $C$2:$C$9, C2, $E$2:$E$9, 0)
Paste to cell D2.
Copy Drag the formula down from the where pasted.
Here we count all the rows for this row's occupation where the occupation matches the range of listed occupations and for that particular row in the list of occupations, the helper column row value is zero.

Answer 4

Add a final column which is the concatenation of the prior 3 columns then use
=SUMPRODUCT(1/COUNTIF(D2:D9,D2:D9))
There is a good explanation of this formula here. Basically, values that appear once will count as 1. Values that appear more than once will appear as fractions of their total occurrence count and be summed to 1.
If you convert your data to an Excel table by selecting a populated cell in the range and pressing Ctrl+T, then formulas will auto-populate down last column. You can then reference the table columns in the formula and you won't need to amend the formula as you add rows.