I have hundreds of "yes" or "no" on column C, and hundreds of "yes" or "no"
on column D, and corresponding student number in each row related to "yes" or
"no".

I want a cell can summary: if in a row, C value is not equal to D value,
student number should listed in this cell. The fact is not too many
difference between column C and column D, so a cell could fit. But I want it
display student number. so, a list of student number.

Is that possible.

Thanks in advance.