重複レコードの検索、削除

  、      : 
　　  :  Group by          
　　 
　　select count(num), max(name) from student --    num    ，        ，     name   
　　group by num 
　　having count(num) >1 -- num       num   ，          
　　delete from student(  Select ) 
　　               。-----   
　　 
　　  :     (  10    ) ,               ,      : 
　　 
　　----     SQL          DRAWING DSNO         
　　 
　　SELECT * FROM EM5_PIPE_PREFAB 
　　WHERE ROWID!=(SELECT MAX(ROWID) FROM EM5_PIPE_PREFAB D --D   First,Second 
　　WHERE EM5_PIPE_PREFAB.DRAWING=D.DRAWING AND 
　　EM5_PIPE_PREFAB.DSNO=D.DSNO); 
　　----     SQL          DRAWING DSNO         
　　 
　　DELETE FROM EM5_PIPE_PREFAB 
　　WHERE ROWID!=(SELECT MAX(ROWID) FROM EM5_PIPE_PREFAB D 
　　WHERE EM5_PIPE_PREFAB.DRAWING=D.DRAWING AND 
　　EM5_PIPE_PREFAB.DSNO=D.DSNO);