If you only need to do a single lookup, you can do that by adding two new columns in your log sheet:
Sheet1
| A | B | C | D | E | F
1 | Tom | xyz | 6/2/2012 | | * | *
2 | Dick | foo | 5/2/2012 | | * | *
3 | Tom | bar | 6/1/2012 | | * | *
Sheet2
| A | B | C
1 | Tom | =Sheet1.E1 | =Sheet1.F1
*(E1) = =IF(AND($A1=Sheet2.$A$1;E2=0);B1;E2)
(i.e. paste the formula above in E1
, then copy/paste it in the other cells with *
)
Explanation: if A is not what you're looking for, go for the next; if it is, but there is a non-empty next, go for the next; otherwise, get it. This way you're selecting the last one corresponding to your search. I'm assuming you want the last entry, not "the one with the most recent date", since that's what you asked in your example. If I interpreted your question wrong, please update it and I can try to provide a better answer.
Update: If the log dates can be out of order, here's how you get the last entry:
*(F1) = =IF(AND($A1=Sheet2.$A$1;C1>=F2);C1;F2)
*(E1) = =IF(C1=F1;B1;E2)
Here I just replaced the test F2=0
(select next if non-empty) for C1>=F2
(select next if more recent) and, for the other column, select next if the first test also did so.
Disclaimer: I'm very inexperienced with spreadsheets, the solution above is ugly but gets the job done. For instance, if you wanted a 2nd row in Sheet2 to do another lookup, you'd need to add two more columns to Sheet1, etc.