title: HANA Query: CASE WHEN, without SELECT Statment
body: <p>I want to understand the CASE WHEN Statment in SAP HANA Query.</p>
  
  <p>It is now to write a Value in a Column, only if there is a Value in the Column before.
  "$[$3.U_chsBestNr2.0]" is the Column before (i get the value of this Column with this Statement).</p>
  
  <pre><code>CASE WHEN $[$3.U_chsBestNr2.0] &lt;&gt; '' THEN
  SELECT T1."Name"
  FROM OPOR T0  
  LEFT JOIN "@CHS_BEL_BELEGTYP" T1 ON T0."U_chsBelTyp" = T1."Code"
  WHERE T0."DocEntry" = $[$3.U_chsBestNr2.0] AND T0."DocStatus" = 'O'
  END CASE
  </code></pre>
  
  <p>The Error appear always as follow:</p>
  
  <pre><code>...257 sql error: incorrect syntax near "CASE"..
  </code></pre>