title: Update table equalize where same id but different country
body: <p>I have a problem creating an SQL statement that would run in a cronjob every few minutes.</p>
  
  <p>I want to equalize one column where <code>ItemCode</code>s (IDs) are the same but each country is different</p>
  
  <p>Table: </p>
  
  <pre><code>+----------+--------+---------+
  
  | ItemCode | OnHand | country |
  
  +----------+--------+---------+
  
  | 08040    | 450    | de      |
  
  +----------+--------+---------+
  
  | 08040    | 000    | hu      |
  
  +----------+--------+---------+
  
  | 08040    | 145    | si      |
  
  +----------+--------+---------+
  </code></pre>
  
  <p>I want to take <code>OnHand where country = de</code> and put it in <code>OnHand where country = hu</code>. (for multiple <code>ItemCode</code> - have 7000 of them)</p>
  
  <pre><code>UPDATE sap_items
      ON sap_items.ItemCode = sap_items.ItemCode AND
         sap_items.country='de'
  SET sap_items.OnHand = sap_items.OnHand
  WHERE sap_items.country='hu'";
  </code></pre>
  
  <p>I understand that this is wrong. But i'm not sure how to properly put it. </p>