title: SQL UPDATE statement with WHERE EXISTS
body: <p>Im trying to write a query that updates a date only if the group im updating has a LINE_CD of 50.  Would i do it like this?</p>
  
  <pre><code>UPDATE EMPLOYER_ADDL  
  SET EMPLOYER_ADDL.GTL_UW_APPRV_DT = EMPLOYER_ADDL.DNTL_UW_APPRV_DT 
  WHERE EXISTS
      ( 
        SELECT EMP_PLAN_LINE_INFO.LINE_CD
        FROM EMP_PLAN_LINE_INFO
        Where EMP_PLAN_LINE_INFO.GR_NBR = EMPLOYER_ADDL.GR_NBR and
         EMP_PLAN_LINE_INFO.LINE_CD = 50
       )
  </code></pre>