Group-By workaround for optimization

Question

This Group By is taken much more time than expected. Recent stats shows it took nearly 14 minutes. Is there any alternative/suggestion for it?
select C.ekey,C.gid,A.ecd,B.pyear, SUM(A.rate) as sum_rate,SUM(A.hrs) AS sum_hrs, SUM(A.amt) as sum_amt
from table_a A,table_b B, table_c C, table_d D,
(SELECT fx_time_key time_key FROM dual) tk
where to_char(D.end_date,'yyyy') = B.pyear
AND C.time_key = tk.time_key
AND C.eno = A.eno
AND D.eno = A.eno
AND D.cid = A.cid
GROUP BY C.ekey,C.gid,A.ecd,B.pyear
Message was edited by:
joshuaa

Answer 1

SELECT STATEMENT                           Cost = 740     
  SORT GROUP BY       
    MERGE JOIN CARTESIAN       
      TABLE ACCESS BY INDEX ROWID     table_c      
        NESTED LOOPS        
          HASH JOIN        
            HASH JOIN        
              TABLE ACCESS FULL          table_b      
              TABLE ACCESS FULL      table_d
            TABLE ACCESS FULL           table_a     
          INDEX RANGE SCAN           E_INDX      
      BUFFER SORT       
        TABLE ACCESS FULL DUAL      Could u make anything out of this?