SELECT pp.toyear, pp.grouptypeid, pp.subjectid, se. * FROM djs_skpaper AS pp INNER JOIN djs_skexam AS se ON se.grouptypeid = pp.grouptypeid WHERE se.grouptypeid =1 AND se.subjectid =1 ORDER BY pp.toyear DESC LIMIT 0 , 30 建议好好看一下MYSQL连接查询部分 !
SELECT pp.toyear, pp.grouptypeid, pp.subjectid, se. * FROM djs_skpaper AS pp, djs_skexam AS se WHERE se.grouptypeid = pp.grouptypeid and se.grouptypeid =1 AND se.subjectid =1 ORDER BY pp.toyear DESC LIMIT 0 , 30 ;
FROM djs_skpaper AS pp, djs_skexam AS se
WHERE se.grouptypeid = pp.grouptypeid
and se.grouptypeid =1 AND se.subjectid =1
ORDER BY pp.toyear DESC
LIMIT 0 , 30 ;
而 se.grouptypeid 和 pp.grouptypeid 均不唯一
自然就多出许多记录了你还需要有 se.toyear=pp.toyear