title: MySQL Join is multiplying the result
body: <p>I am having issues joining two tables together, it keeps multiplying my value "qtyFulfillable".</p>
  
  <p>1st, when I run this query, I get the correct result: <strong>sumQF = 85</strong></p>
  
  <pre><code> SELECT fbai.id, 
          fbai.sku,
          CASE WHEN SUM(fbai.qtyFulfillable) &gt; 0 THEN SUM(fbai.qtyFulfillable) ELSE 0 END AS sumQF
   FROM FBAInventory fbai
   WHERE fbai.fbaInventoryReport_id = 62010
   AND     fbai.sku = 'ELO-250030'
   GROUP BY fbai.id
   ORDER BY sumQF DESC
  </code></pre>
  
  <p>But when I start adding in the join, I now get: <strong>sumQF = 14110</strong></p>
  
  <pre><code> SELECT fbai.id, 
          fbai.sku,
          CASE WHEN SUM(fbai.qtyFulfillable) &gt; 0 THEN SUM(fbai.qtyFulfillable) ELSE 0 END AS sumQF, 
          CASE WHEN   SUM(fbas.quantityShipped) &gt; 0 THEN SUM(fbas.quantityShipped) ELSE 0 END as sumQS
   FROM FBAInventory fbai
   LEFT JOIN  FBAShipment fbas
   ON fbai.sku = fbas.sku
   WHERE fbai.fbaInventoryReport_id = 62010
   AND     fbai.sku = 'ELO-250030'
   GROUP BY fbai.id
   ORDER BY sumQF DESC
  </code></pre>
  
  <p>For some reason the sql taking the total number of rows in the "fbas" table (the joined table), 166 rows, and multiplying <strong>85 x 166 = 14110</strong>. </p>
  
  <p>What do I need to do to be able to join in this table yet keep it from multiplying my result by the total number of rows in the joined table. Thanks!</p>