Test whether a value appears anywhere in another column or list.
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=IF(COUNTIF(B:B, A2)>0, "Yes", "No")COUNTIF counts how many times the value appears; greater than zero means it exists. IF turns that into a readable Yes/No. It's the simplest way to compare two lists for membership.
=IF(COUNTIF(Approved, A2)>0, "✓", "")→✓Marks rows whose ID is in the approved list.
Using MATCH
=IF(ISNUMBER(MATCH(A2, B:B, 0)), "Yes", "No")MATCH + ISNUMBER also tests existence.
Flag with =IF(COUNTIF(ListB, A2)=0, "Missing", ""), then filter for "Missing".
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