Indicate min priority of identical terminal in the same day

You can use:

=IF(C2=AGGREGATE(15,6,$C$2:$C$8/(($A$2:$A$8=A2)*($B$2:$B$8=B2)),1),"OK","Not OK")

this would be one way but it is using a helper column. Put this in column E or somewhere... {=MIN(IF(($A$2:$A$8=A2)*($B$2:$B$8=B2),$C$2:$C$8))}
Note that is an array formula so past in to a cell this... =MIN(IF(($A$2:$A$8=A2)*($B$2:$B$8=B2),$C$2:$C$8)) then with your cursor in the formula bar hit ctrl + shift + enter all at the same time so these braces appear on each end {}, that means the formula is activated - YOU CANNOT add them. Then drag toward down.

Next, put this formula in another column =IF(E2=C2,"ok","not ok")
drag both down.

Sigh, I kept waiting for someone to give the OP a better answer than that array with helper column, THANKS Glenn for providing it.

you should update your attachment so additional columns and conditions can be accounted for.

can you explain how you want the outcome this time? Does a later time but lower priority number take place over the earlier time with a higher priority? And you didn't include ties, how do you want ties handled?
The way Glenn's formula is working is that it is pulling the lowest number based on the terminal ID and Date, it works because you have the same terminal ID and same Date more than once. If you add hour into it you now have distinct events again which defeats the formula. So applying what I believe is the logic Glenn used all come out as ok.
you should add the outcomes you expect to your workbook.

Yes. Your sample is incorrect. There are NO rows with same terminal/same date/same priority. So, udate it again. AND show your expected answers - if there are two priority 1s... which one is "OK and which one is "Not OK"... and WHY?

Check this one. I will see if I can find a cleaner way to do this.

This is not so simple. It returns as expected (shadowed in column F). It must be array entered in F2 and filled down.

If you aren’t familiar with array-entered formulas array enter means the formula must be committed from edit mode by simultaneously pressing and holding down Ctrl and Shift while hitting Enter.

Formula:

Please Login or Register  to view this content.

A non CSE version of this can be done but would be much longer. Will post if you prefer.

BTW is your profile current?

Office 365 (and maybe Office 2019?) have the MINIFS function that would make short work of this.

Formula:

Please Login or Register  to view this content.