title: how does "case when index" statement compare to "case index" statement
body: <p>I tried to research about this command, but I can't seem to find a concrete explanation to it.</p>
  
  <p>What is "case when index"? what does it do? how is it differ from case when?
  When is it used? 
  Is this available to other RDMS or is it Teradata specific?
  I would really it if you could provide some examples also. </p>
  
  <p>Thank you so much.</p>
  
  <pre><code>sel
  CASE    WHEN .00 = 0 THEN 0||'.' 
  ELSE    .00 
  END
  ,CASE   WHEN INDEX (.00,'.') = 0 THEN 0||'.' 
  ELSE    .00 
  END
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>  0.     .00
  </code></pre>