title: Merge multiple Excel workbooks based on key column
body: <p>I get seven workbooks (xlsx files) from different clients, each with one sheet.</p>
  
  <p>Each sheet has at least one common ID column (UNIQ, PK). One of the workbook contains list of all possible ids. Others may not have record for all ids, but each row has id value defined.</p>
  
  <p><strong>I need to make a final workbook, with first column ID and then union of all remaining columns from each file.</strong></p>
  
  <p>Then I need to send the <code>final.xlsx</code> via email, so its independent of the source files (I'm not sure if its possible to dereference it while retaining the constant values).</p>
  
  <p>Can we do this using <code>VLOOKUP</code> or built-in Excel functions?</p>