title: Excel Formula for Comparing 4 Columns but Treating 2 Columns together?
body: <p>I am trying to compare 4 columns (or 2 columns in each sheets).</p>
  
  <p>Whether the price for the SKU has changed or not. The data isn't sorted so the range have to be by columns.</p>
  
  <p>I get error using below formula...</p>
  
  <p><code>IF(COUNTIF("a:a" &amp; "b:b","c:c" &amp; "d:d")&gt;0,"",Changed)</code> or </p>
  
  <p><code>=IFERROR(INDEX(A:B,MATCH(A1,A:A,0)),"",Changed)</code> but the data isn't always sorted</p>
  
  <pre><code>Column(A+B)    Column(C+D)
  SKU  Price     SKU  Price
  AAA  59.95     DDD  129.99
  BBB  49.95     BBB  159.00    Changed
  CCC  49.95     CCC  159.00    Changed
  DDD  129.99    AAA  59.99
  </code></pre>