title: Merge/Union multiple data sources
body: <p>I've got 4 excel files that have the exact same columns, they are just simply broken out by Quarter.  This is needed because the automated system can't handle too large of files.</p>
  
  <p>In Tableau I've connected to each data source and called them Q1/Q2/Q3/Q4.  </p>
  
  <p>How can I get this to all work as one single year?</p>
  
  <p>I've explored joining, and read articles talking about Custom SQL Unions.  That doesn't work, it seems to only let me do a Union between Worksheets in the same Workbook.  They're different Workbooks, and hence different data sources.</p>