title: Using Tableau to do VLookup
body: <p>New to Tableau so sorry if this is obvious, but I had a hunt and couldn't find/understand anything.  So I have a cake shop and I want to know if people have purchased both éclairs and Eccles cakes in the same order</p>
  
  <pre>ORDER ID     item 
  0001         éclair
  0001         iced bun
  0001         Eccles cake
  0002         éclair 
  0002         iced bun
  0003         éclair          
  0003         Eccles cake     </pre>
  
  <p>What I want as an output is the following:</p>
  
  <pre>
  ORDER ID     item          éclair?
  0001         éclair          0
  0001         iced bun        0
  0001         Eccles cake     1
  0002         éclair          0
  0002         iced bun        0
  0003         éclair          0
  0003         Eccles cake     1
  </pre>
  
  <p>I'm thinking it requires something like a lookup, or a helper column?!</p>
  
  <p>For reference, I've got a single data set (a csv file) so I'm guessing I can't run a SQL query on it?</p>