Comments on: Writing SQL queries http://psoug.org/blogs/mohan/2010/04/23/writing-sql-queries/ Real-World Oracle Tips And Techniques Tue, 14 Dec 2010 23:00:50 +0000 hourly 1 http://wordpress.org/?v=3.5.1 By: Pleiadian http://psoug.org/blogs/mohan/2010/04/23/writing-sql-queries/comment-page-1/#comment-5 Pleiadian Fri, 23 Jul 2010 14:10:25 +0000 http://psoug.org/blogs/mohan/?p=76#comment-5 Don't try the suggestions in "Eliminating duplicate values in a table"
<code>
Method 1:
———
  DELETE FROM emp a
    WHERE rowid > (
      SELECT min(rowid)
      FROM   emp b
      WHERE  a.emp_id = b.emp_id
    );
</code>
This will delete a lot more…
And I would not reccomend:
<code>
Original Statement:
  SELECT  dname, loc
  FROM    dept
  WHERE   loc = 'CHICAGO'
     OR   loc = 'NEW YORK';

New Statement:
  SELECT  dname, loc
  FROM    dept
  WHERE   loc = 'CHICAGO'
  UNION ALL
  SELECT  dname, loc
  FROM    dept
  WHERE   loc = 'NEW YORK';
</code>
But rather:
<code>
  SELECT  dname, loc
  FROM    dept
  WHERE   loc in ('CHICAGO','NEW YORK');
</code>
 

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