进销数据生成唯一排列号的办法之一

SELECT C.ENTID,C.DATES,C.ONTIME,C.BILLNO,C.BILLSN
      ,'Z'||SUBSTR('0000000000',1,10 - LENGTH(ROW_NUMBER()OVER(ORDER BY C.ENTID,C.DATES,C.ONTIME,C.BILLNO,C.BILLSN)))||ROW_NUMBER()OVER(ORDER BY C.ENTID,C.DATES,C.ONTIME,C.BILLNO,C.BILLSN) AS ID
FROM (
      SELECT  A.ENTID,A.DATES,A.ONTIME,A.BILLNO,B.BILLSN
      FROM PURINMT A
           INNER JOIN PURINDT B ON A.ENTID = B.ENTID AND A.BILLNO = B.BILLNO
      UNION ALL 
      SELECT  A.ENTID,A.DATES,A.ONTIME,A.BILLNO,B.BILLSN
      FROM SALEOUTMT A
           INNER JOIN SALEOUTDT B ON A.ENTID = B.ENTID AND A.BILLNO = B.BILLNO
      UNION ALL 
      SELECT  A.ENTID,A.DATES,A.ONTIME,A.BILLNO,B.BILLSN
      FROM ALEXECMT A
           INNER JOIN ALEXECDT B ON A.ENTID = B.ENTID AND A.BILLNO = B.BILLNO
     ) C
;

由上语句生成一个View，需要时，根据BILLNO和BILLSN去取