select * from (SELECT DISTINCT a.WJBM,a.SWDJDM,a.JC_NSR,b.rq_sb FROM zzds.DJ_NSR_JBXX a,zzds.SB_DZQCLS b,zzds.DM_DLWZ_QX c,zzds.DM_DLWZ_JD d where a.WJBM = b.WJBM AND a.DM_ZCD_QX = c.DM_DLWZ_QX(+) AND a.DM_ZCD_JD = d.DM_DLWZ_JD(+) AND (b.RQ_SB IS NULL or SUBSTR(b.rq_sb,1,7)='2004-03') ) a
where rownum<200
where rownum<200
在有rownum条件的时候一般最后才执行
where rownum<200