Ò»¸ösqlÓï¾ä

        SELECT min_cons_amount
              from min_cons_history
            WHERE min_cons_acct = 225280001
              AND min_cons_effective_date <= to_date(20110101,'yyyymmdd')
              and rownum=1
          order by min_cons_effective_date desc


min_cons_history ±íÀïmin_cons_acct = 225280001 ÓжàÌõ  ÎÒÏÖÔÚÒª°´min_cons_effective_date½µÐòÅÅÁÐÈ¡µÚÒ»Ìõ

ÉÏÃæµÄÓï¾ä²»ÄÜÂú×㣬ÒòΪrownum=1ÔÚorder by ֮ǰ¾ÍÈ¡ÁË¡£¡£¡£
ºÃÏñÒªÓиöǶÌײéѯ£¬µ«ÎÒÍü¼ÇÔõôдÁË¡£

---

ÒªÏÈÅÅÐòÔÙÈ¡ROWNUM=1

---

select * from £¨SELECT min_cons_amount
              from min_cons_history
            WHERE min_cons_acct = 225280001
              AND min_cons_effective_date <= to_date(20110101,'yyyymmdd')
                        order by min_cons_effective_date desc ) where rownum=1

---

select * from
( SELECT min_cons_amount
              from min_cons_history
            WHERE min_cons_acct = 225280001
  &