查询失败 select a.id,a.author,a.pic,a.title,a.is_gen,b.tid,c.id as tagid,c.litpic,c.sname,c.descrp from book a left join book_taglist b on a.id=b.aid left join tagindex c on b.tid=c.id where b.tid= and a.exam=1 and a.del=0 and a.state=0 and c.del=0 order by a.uptime desc limit 8 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'and a.exam=1 and a.del=0 and a.state=0 and c.del=0 order by a.uptime desc limit ' at line 1