title: break from a case early
body: <p>I have been having a terrible time with this code. I was wondering if someone could look and tell me how to either break out of the case statement if the CC_LIST contains a matching value already. It keeps concatenating and I want it check for an email address mapped by the join and then break if the email address is present. Below is my code:</p>
  
  <pre><code>UPDATE HD_TICKET
  
  JOIN USER ON USER.FULL_NAME = CUSTOM_FIELD_VALUE11
  
  SET HD_TICKET.CC_LIST =
  
  CASE WHEN HD_TICKET.CC_LIST = '' OR HD_TICKET.CC_LIST IS NULL THEN USER.EMAIL 
  ELSE CONCAT(HD_TICKET.CC_LIST, ", ", USER.EMAIL)
  END 
  where HD_TICKET.HD_QUEUE_ID = 12 
  </code></pre>