title: Coalesce datetime values and convert to varchar
body: <p>I have the following in my query:</p>
  
  <pre><code>( case
    when clientplans.start_date='1899-12-30 00:00:00.000' then ''
    else CONVERT(varchar,clientplans.START_DATE,112)
    end
  ) as POLICY_EFF_DATE,
  </code></pre>
  
  <p>I am getting some NULLs which I need to COALESCE to empty strings.</p>
  
  <p>I tried the following, among other variations, without success:</p>
  
  <pre><code>( case
    when clientplans.start_date='1899-12-30 00:00:00.000' then ''
    else COALESCE( CONVERT(varchar,clientplans.START_DATE,112) , '' )
    end
  ) as POLICY_EFF_DATE,
  </code></pre>
  
  <p>How can I get rid of the NULLs?</p>