Lookup w/ aliases

Hi,

basically, I'm taking your INDEX/MATCH formula, but before applying the MATCH, the formula check sif the MATCH returns an error. If so, it goes on to try and find a match in the next column, and so on.

break it down into bits like this

=INDEX(Sheet2!$A$2:$A$4,
    ' now the MATCH bit
    IF(
         ISNA(MATCH(Sheet1!$B3,Sheet2!$B$2:$B$4,0)),  ' if match is an error in column B then
               'look at column C
               IF(
                     ISNA(MATCH(Sheet1!$B3,Sheet2!$C$2:$C$4,0)), ' if match is an error in column C then
                                'look at column D and return this for MATCH
                                MATCH(Sheet1!$B3,Sheet2!$D$2:$D$4,0),
               'else = if a match is found in column C, return this for MATCH
                                MATCH(Sheet1!$B3,Sheet2!$C$2:$C$4,0)),
               ' end of inner IF
         'else = if a match is found in column B, return this for MATCH
         MATCH(Sheet1!$B3,Sheet2!$B$2:$B$4,0)))
     'end of outer IF