title: DB2 Update with join queries
body: <p>I am using DB2 for performing the below update operation.</p>
  
  <pre><code>update DATA set B_DESC=P_DESC, P_DESC=null
  where B_DESC= *, P_DESC=*
  (Select B_DESC,P_DESC from C_DATA) 
  </code></pre>
  
  <p>The below is actually possible but since complex joins are involved in that sub query it is not advisable to use like below </p>
  
  <pre><code>update DATA set B_DESC=P_DESC, P_DESC=null
  where B_DESC= (Select B_DESC from C_DATA), P_DESC=(Select P_DESC from C_DATA)
  </code></pre>
  
  <p>I have to update DATA table, but the B_DESC and P_DESC i have to fetch it from C_DATA table and use it in the UPDATE query.</p>
  
  <p>Please let me know how to do it. It has to be a single query if possible.</p>
  
  <p>Thanks in advance.</p>