need to lookup a value in one column to fill in another

[Guest]

I have only 4 columns in a log book, the first is the Customer name the
second is the customer number, the other two are some date columns. I've
been manually entering the customer name and number for the past year. I
want to be able when adding a new row to type in the customer number and it
will lookup above to find the customer name. is there anyway to do this?
thanks

 

[Don Guillett]

No pun intended but lookin the help index for LOOKUP or MATCH

 

[Guest]

one suggestion using Index/Match - assuming customer names are in column A
and customer number is in column B, try entering this in the next empty row
of column A (let's assume row 20 is the next available slot)

so A20 would be
=INDEX(A$1:A19, MATCH(B20, B$1:B19, 0))

adjust the range references as needed, but keep the $ where they are. then
copy the formula down column A as far as needed.