title: Performance tuning in teradata for view
body: <p>I have created a view as below :</p>
  
  <pre><code>REPLACE    VIEW EDB_MAN_VWS.EMP AS
  LOCKING    ROW FOR ACCESS   (
    SELECT 'P2' AS REGION_CD , a.* FROM EDB_MAN_WORK.EMP_IND a
    UNION 
    SELECT 'Z2' AS REGION_CD , b.* FROM EDB_MAN_WORK.EMP_US b
    UNION 
    SELECT 'I2' AS REGION_CD , c.* FROM EDB_MAN_WORK.EMP_UK c
  );
  </code></pre>
  
  <p>I am running below query on the view but this is taking time.</p>
  
  <pre><code>SELECT EMP_IND.CUST_NO,EMP_US.REGION_CD,EMP_UK.CUST_TYPE
  FROM EDB_MAN_VWS.EMP_IND,
       EDB_MAN_VWS.EMP_US,
       EDB_MAN_VWS.EMP_UK
  WHERE EMP_UK.CNTL_ENT_no = EMP_US.CNTL_ENT_no
  AND EMP_US.CUST_no = EMP_IND.CUST_no
  AND EMP_UK.REGION_CD = EMP_US.REGION_CD
  AND EMP_US.REGION_CD = EMP_IND.REGION_CD
  GROUP BY  CUST_NO,REGION_CD,CUST_TYPE
  </code></pre>
  
  <p>I want to tune this query but we cant create SI on the view.
  Please help me in optimizing this query.</p>