title: MySQL SUM multiple columns in same ROW
body: <pre><code>+---------------+---------+-----------------+---------+ 
  | product_count | size1   | sproduct_count2 | size2
  +---------------+---------+-----------------+---------+ 
  |            13 | 2x4     |               5 |     2x6 
  |            14 | 2x6     |               2 |     4x8 
  |            15 | 2x8     |               3 |     2x8 
  |            16 | 4x4     |               2 |     4x4 
  |            17 | 4x8     |              15 |     4x8
  +---------------+---------+-----------------+---------+
  </code></pre>
  
  <p>How do I get the total counts so the return results appear like:</p>
  
  <pre><code>product_count | size
             13 | 2x4
             19 | 2x6
             18 | 2x8
             18 | 4x4
             34 | 4x8
  </code></pre>
  
  <p>I have tried:</p>
  
  <pre><code>SELECT SUM(product_count+product_count2) AS product_count, size1 FROM UNITS GROUP BY size1
  </code></pre>
  
  <p>and it works for some rows and others it does not work for. Would CONCAT be something I need to use?</p>