麻烦各位老师给看看这条SQL语句的问题出在哪里？

[zpingfang]

select distinct a.diqu,a.kahao,a.CheckInNo,a.piaolei,a.ZhengJian,a.CheckInTime,a.RenShu,b.mingcheng,c.mingma,d.mingcheng as mch,e.mingcheng as pl,f.DFMingCheng as zj,g.Expr1 as cf from(select k.CheckInTime,k.RenShu,k.diqu,k.kahao,k.checkinno,k.piaolei,k.ZhengJian from Tbl_checkIn k,(select max(id) as id,zhengjian from Tbl_checkIn group by zhengjian) b where k.id=b.id) a,tbl_diqu b,tbl_ShouPiao c,tbl_YanPiaoDian d,tbl_PiaoLei e,Tbl_SFZ f,zgUser.tbl_S g where a.diqu=b.bianhao and a.KaHao=c.kahao and a.CheckInNo=d.bianhao and left(a.zhengjian,6)=f.SFZBianHao and a.piaolei=e.bianhao and a.ZhengJian=g.ZhengJian and mingma>='18001' and mingma<='18205' order by a.ZhengJian


首先说下这条语句是朋友帮我写的，我的学艺不精，麻烦各位老师帮忙看下这个语句，之前没加g.Expr1、zgUser.tbl_S g，a.ZhengJian=g.ZhengJian这三句是能查出数据的，但是加完后就不显示结果了，也没有报错查询结果为空，g.Expr1表项是证件的使用次数，a.ZhengJian=g.ZhengJian这个筛选条件写法有错误吗？请各位老师帮忙给看下，谢谢啦！

[茫茫前路]

楼主把关联这一节的内容研究一下，就很容易发现问题所在了。

[Mr_Nice]

[Quote=引用 2 楼 的回复:]

引用 1 楼 的回复:

SQL code
SELECT DISTINCT
a.diqu ,
a.kahao ,
a.CheckInNo ,
a.piaolei ,
a.ZhengJian ,
a.CheckInTime ,
a.RenShu ,
b.mingcheng ,
c……


但是a表和g表之间zhengjian列的值确实有相同的，g表里记录的是证件和使……
[/Quote]

a,g表单独拿出来，链接一下看看有结果没？
应该还是链接上的问题。

[Mr_Nice]

SELECT DISTINCT
        a.diqu ,
        a.kahao ,
        a.CheckInNo ,
        a.piaolei ,
        a.ZhengJian ,
        a.CheckInTime ,
        a.RenShu ,
        b.mingcheng ,
        c.mingma ,
        d.mingcheng AS mch ,
        e.mingcheng AS pl ,
        f.DFMingCheng AS zj ,
        g.Expr1 AS cf
FROM    ( SELECT    k.CheckInTime ,
                    k.RenShu ,
                    k.diqu ,
                    k.kahao ,
                    k.checkinno ,
                    k.piaolei ,
                    k.ZhengJian
          FROM      Tbl_checkIn k ,
                    ( SELECT    MAX(id) AS id ,
                                zhengjian
                      FROM      Tbl_checkIn
                      GROUP BY  zhengjian
                    ) b
          WHERE     k.id = b.id
        ) a ,
        tbl_diqu b ,
        tbl_ShouPiao c ,
        tbl_YanPiaoDian d ,
        tbl_PiaoLei e ,
        Tbl_SFZ f ,
        zgUser.tbl_S g
WHERE   a.diqu = b.bianhao
        AND a.KaHao = c.kahao
        AND a.CheckInNo = d.bianhao
        AND LEFT(a.zhengjian, 6) = f.SFZBianHao
        AND a.piaolei = e.bianhao
        AND a.ZhengJian = g.ZhengJian    --默认是inner join 的方式，说明在a,g之间，没有对应的zhengjian列的值相同
        AND mingma >= '18001'
        AND mingma <= '18205'
ORDER BY a.ZhengJian


/*
g.Expr1、zgUser.tbl_S g，a.ZhengJian=g.ZhengJian*/

[zpingfang]

[Quote=引用 1 楼 的回复:]

SQL code
SELECT DISTINCT
a.diqu ,
a.kahao ,
a.CheckInNo ,
a.piaolei ,
a.ZhengJian ,
a.CheckInTime ,
a.RenShu ,
b.mingcheng ,
c……
[/Quote]

但是a表和g表之间zhengjian列的值确实有相同的，g表里记录的是证件和使用次数啊