title: "Select case" performance issue
body: <p>I am facing performance issue in below mentioned SQL query : </p>
  
  <pre><code>select column1, 
     (SELECT CASE fl.ISDELETED WHEN 'T' THEN 'T' ELSE 'F' END  FROM FILE fl
       WHERE lower(fl.FILE_TYPE) LIKE 'doc' AND fl.FILE_ID=doc.FILE_ID   ) AS alias1 ,
     (SELECT CASE fl.ISDELETED  WHEN 'T'  THEN 'T' ELSE 'F'  END FROM FILE fl
       WHERE lower(fl.FILE_TYPE) LIKE 'xls'   AND fl.FILE_ID=doc.FILE_ID ) AS alias2
  
  FROM DOC doc
  </code></pre>
  
  <p>Is there any alternative(JOIN or any other option)  of select case statement so that it will take less time to execute? I am calling this query from java code</p>
  
  <p>Any kind of help would be appreciated</p>