title: VLOOKUP by Combining 2 Columns to Form a Unique Key
body: <p>For the following table,</p>
  
  <p><img src="https://i.imgur.com/QmJ1xHl.jpg" alt="excel table"></p>
  
  <p>I want to look up the value in col C. Since the values in col A and col B are not unique, VLOOKUP fails. For example, VLOOKUP(1,table,3) returns 5 and never 1.</p>
  
  <p>However, the <em>combinations</em> of cols A &amp; B are unique. For example, 1blah = 5, while 1foo = 1.</p>
  
  <p>How can I use the combination of cols A &amp; B as a unique key to return the corresponding value in col C?</p>
  
  <p>I'm not sure if this should be implemented with worksheet functions or a custom VBA function. I tried using CONCATENATE to generate the unique key, but this did not work because this results in combinations of numbers and strings.</p>