left join 连接问题

[wch_212]

select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T  t left join  T_SQ tsq on tsq.xq_dm=t.xzqh_dm  , T t1 ,T2 t2
where t1.xzqh_dm=t.ssfw and t2.xzqh_dm=t1.ssfw  group by t.mc,t1.mc,t2.mc order by t2.mc

我还想对T_SQ这个表再连接个表查询怎么做？

[wch_212]

[dawugui]

把他做为子查询?

select m1.* , m2.* from m1,
(
select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm , T t1 ,T2 t2
where t1.xzqh_dm=t.ssfw and t2.xzqh_dm=t1.ssfw group by t.mc,t1.mc,t2.mc order by t2.mc
) m2
where ...

[dawugui]

刚才没看清楚:
你这段:
left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm , T t1 ,T2 t2

什么乱七八糟的?

[304的的哥]

select ......
from t,t_sql,tttd
where t.id(+)=t_sql.id and
t_sql.ttl(+)=tttd.ttl;

[304的的哥]

[Quote=引用 4 楼 bobo12082119 的回复:]
select ......
from t,t_sql,tttd
where t.id(+)=t_sql.id and
t_sql.ttl(+)=tttd.ttl;
[/Quote]
错了!
select ......
from t,t_sql,tttd
where t.id=t_sql.id(+) and
t_sql.ttl=tttd.ttl(+);
一觉睡醒，有点晕

[wch_212]

我补充下吧，


select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm , T t1 ,T2 t2
where t1.xzqh_dm=t.ssfw and t2.xzqh_dm=t1.ssfw group by t.mc,t1.mc,t2.mc order by t2.mc


能查询出来两列

我还想再加一列查询，

加的这一列查询要再用一张表，判断条件和 T_SQ 的一列相同

怎么做？

[304的的哥]

--不知道可不可以
select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm 
     left join new_table nt on T_SQL.id=nt.id,
     T t1 ,T2 t2
where t1.xzqh_dm=t.ssfw and t2.xzqh_dm=t1.ssfw group by t.mc,t1.mc,t2.mc order by t2.mc

[wch_212]

[wch_212]

[Quote=引用 8 楼 bobo12082119 的回复:]

SQL code

--不知道可不可以
select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm
left join new_table nt on T_SQL.id=nt.id,
T t1 ,T2 t2
where t1.xz……
[/Quote]

这个试过了，能查询出来值 ，不过数不对

我想变成这样 红色的是新加的

可是数和蓝色的一样了

select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)，count(nt.id)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm
left join new_table nt on T_SQL.id=nt.id,
T t1 ,T2 t2
where t1.xz……

[304的的哥]

[Quote=引用 9 楼 wch_212 的回复:]

引用 8 楼 bobo12082119 的回复:

SQL code

--不知道可不可以
select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm
left join new_table nt on T_SQL.id=nt.id,
T……
[/Quote]
这说明数据库表里面：tsq.xq_dm)，nt.id的数量相同

[wch_212]

[Quote=引用 10 楼 bobo12082119 的回复:]

引用 9 楼 wch_212 的回复:

引用 8 楼 bobo12082119 的回复:

SQL code

--不知道可不可以
select (t2.mc||t1.mc||t.mc) as mc,count(tsq.xq_dm)
from T t left join T_SQ tsq on tsq.xq_dm=t.xzqh_dm
left join new_table n……
[/Quote]

不是，只有一条匹配的。

[304的的哥]

--原句：怎么T表重复出现两次？加‘*’号的地方，
select (t2.mc||t1.mc||t.mc) as mc,
       count(tsq.xq_dm)
from T  t left join  T_SQ tsq 
     on tsq.xq_dm=t.xzqh_dm  , 
     *T t1 ,T2 t2
where t1.xzqh_dm=t.ssfw and 
      t2.xzqh_dm=t1.ssfw  
group by t.mc,t1.mc,t2.mc 
order by t2.mc
--难道是这样
select (t2.mc||t1.mc||t.mc) mc,
       count(tsq.xq_dm) xq_dm
from T t left join T_SQ tsq 
     on tsq.xq_dm=t.xzqh_dm 
        left join new_table nt 
     on tsq.id=nt.id,
     T1 t1 ,T2 t2
where t1.xzqh_dm=t.ssfw and 
      t2.xzqh_dm=t1.ssfw 
group by t.mc,t1.mc,t2.mc 
order by t2.mc
--不管怎么样，你的表字段命名太丑了，用英文单词多好记啊!
--我想着也是影响你的一个原因吧！

[wch_212]

自己解决了……

[wch_212]

加了，一堆 left join on .

[304的的哥]

自学成才！