compare and merge data
 

For the life of me I cannot figure this one out... I have two seperate
worksheets. Worksheet 1 has 3 columns (Column A: old-Acct, Column B:
new-Acct, Column C: Index); Worksheet 2 has 2 colums (Column A: old-Acct,
Column B: Index). I would like to merge data from both into one. If wk1
Column A: old-Acct = wk2 Column B: old-Acct then place wk2 Column B: index in
wk1 Column C: index and if Wk2 Column A: old-Acct does not exist in wk1
Column A: old-Acct; then place wk2 Column A: old-Acct in wk1 Column A:
old-Acct and place (same row) wk2 Column B: index in wk1 Column C: index.

I hope this makes sense and thanks in advance for the help!