countif - issue (no duplicates)

Hello

Can someone tell me what im doing wrong with this?

=IF(ROWS($52:52)>COUNTIF(Data!$CX$12:$CX$75,Calculations!$E$51),"",INDEX(Data!$CW$12:$CW$75,SMALL(INDEX(ROW(Data!$CX$12:$CX$75)+(Data!$CX$12:$CX$75<>Calculations!$E$51)*10^10,0),ROWS($52:52))))

there should be a total of 13 entries.

so after 13 entries, the formula should give a zero result.....but this appears to not be happening, any ideas why?

basically, this lets me not get any duplicate values from the list taht i have. thx you so much!

Are you confirming with CTRL+SHIFT+ENTER and then copied down?

If yes and still an issue, can you post sample spreadsheet?

Try this formula in U52 copied down

=LOOKUP("zzz",IF({1,0},"",INDEX(Data!$CW$12:$CW$75,MATCH(1,INDEX(ISNA(MATCH( Data!$CW$12:$CW$75,U$51:U51,0))*(Data!$CX$12:$CX$75=E$51),0),0))))

it doesn't need "array entering"....

Try:

=LOOKUP(REPT("z",255),CHOOSE({1,2},"",INDEX(Data!$CW$12:$CW$76,MATCH(0, INDEX(COUNTIF(Calculations!C$51:C51,Data!$CW$12:$CW$75),0),0))))

confirmed with just ENTER and copied down.

For me, my formula gave the exact same results as daddylonglegs' formula...