There's an easy solution to the first part of this one, Steve, but a
surprising number of Excel users seem to be unfamiliar with it so you're in
plentiful company. I'll just tell you the bare bones; you can probably gussy
it up pretty without further help. In some column in sheet A to the right of
column A (where the emp numbers are), on row 3 let's say, type this formula:

=MATCH(A3,SheetB!A3:A253,0)

This looks in A3:A253 (or whatever your search range should be) on SheetB
for the emp number in column A of this row. If it finds that exact value, it
displays the row number in this cell; otherwise it displays #N/A. If it
finds the value you can use the row number with INDIRECT to compare the
days-off values; if it didn't, the ISERROR test can be used to display the
aviso that it's not on the list at all.

Do the same in SheetB to match the other way.

--- "Steve" wrote:
I have some employee data from two different sources (on two separate tabs).

On 3rd tab, I'd like to show if the data is on sheet A , but not on sheet
B, and vice-versa. E.g.

Sheet A
Employee ID Name
12345 John
78910 Mary
45678 Joe

Sheet B
Employee ID Name
12345 John
45678 Joe
77777 Jill


So I'd like to have in Sheet C something to the effect of:
Mary is in sheet A, but not B &
Jill is in sheet B, but not A.

Another thing I'd like to be able to do is:

One of the sheets shows days off as follows
NNNNYYN Y's meaning they're off Wed & Thurs
the other sheet shows WedThu as their days off
Can I also get someting to indicate that for that particular employee ( ID)
if NNNNYYN meaning off Wec & Thu on one sheet, but shows FriSat on the other,
to produce an Alert such as "day offs don't match"" ?