title: Case statement resolved with ERROR - FROM keyword not found where expected
body: <p>I try to execute a query and on the fly to create a new column which its value depends on other columns using case statements. Note that RATE is a new column that does not exist in the table. can you please tell me where am i wrong?</p>
  
  <pre><code>SELECT PAY_ATTR1.ID,
         PAY_ATTR1.AMOUNT,
         PAY_ATTR1.TAX,
         ISSYNC = CASE WHEN PAY_ATTR1.AMOUNT != PAY_ATTR2.AMOUNT THEN 'DIFF' ELSE NULL END 
  FROM PAY_ATTR1
      INNER JOIN PAY_ATTR2
      ON PAY_ATTR1.ID=PAY_ATTR2.ID
  </code></pre>
  
  <blockquote>
    <p>ORA-00923: FROM keyword not found where expected</p>
  </blockquote>