SQL needed

[donna lester <donna_lester_ny@xxxxxxxxx>]

select SUM(CASE WHEN PVAL>0 THEN PVAL ELSE 0 END)       
 AS USVAL  FROM USA/ATSFILE                          
WHERE PCNTRY<>'US' AND                                      
      PDATE BETWEEN 20070401 AND 20070630   AND            
      PSYMBOL                                                 
IN('7V','99','03','03') AND PSUBSYM ='B'                     
                                                                                                             
I want to improve the above SQL so that sum should be calculated only when pfa,pofc,pacc of ATSFILE equal to pfa,pofc&pacc of ATSUSFILE.
Iam not familiar using "With" in SQL , can some one help me to get improved SQL.



Thanks,

Donna.
       
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