Excel data mapping

I have two different data sheets in excel like below.

1st: A is first column B is second

A -> B

2nd: B is first column C is second

B -> C

I want to add them together so I can get

A -> B -> C values mapped correctly.

The problem is there is about 50K value in each column, some of them are empty and values are not in order.

Thanks in ad开发者_如何转开发vance.

You can use the VLOOKUP formula on the C column of the first sheet

See this link or this one to understand how to use the VLOOKUP statement.

If you want more precise help, show us some data so that we will help you building the formula.