子查询的款困惑

本帖最后由 zhaoyh603 于 2011-02-15 21:47 编辑

select (select a.dept_fullname from ad_department a where a.dept_id = parent_id)||'_'||dept_name as b ,dept_name,parent_id from ad_department
Where Length(dept_Code) = 6 And dept_Code Like '99%' ;

b是空的

select b.dept_fullname||'_'||a.dept_name as b , a.dept_name from ad_department a,ad_department b where a.parent_id=b.dept_id;

可以

目的是想update dept_fullname

为什么呀疑惑

作者: zhaoyh603 发布时间: 2011-02-15

本帖最后由 zhaoyh603 于 2011-02-15 21:47 编辑

select (select a.dept_fullname from ad_department a where a.dept_id = b.parent_id)||'_'||b.dept_name as b ,b.dept_name,b.parent_id from ad_department b
Where Length(b.dept_Code) = 6 And b.dept_Code Like '99%' ;

加了别名就可以了，晕 why

作者: zhaoyh603 发布时间: 2011-02-15

本帖最后由 zhaoyh603 于 2011-02-15 21:48 编辑

update ad_department as b
set b.dept_fullname=(select a.dept_fullname from ad_department a where a.dept_id = b.parent_id)||'_'||b.dept_name
Where Length(b.dept_Code) = 6 And b.dept_Code Like '99%' ;

错误：
ERROR: column "b" of relation "ad_department" does not exist
LINE 2: set b.dept_fullname=(select a.dept_fullname from ad_departme...

作者: zhaoyh603 发布时间: 2011-02-15

晕呼，没看明白。

作者: renxiao2003 发布时间: 2011-02-15

本帖最后由 zhaoyh603 于 2011-02-15 21:48 编辑

update ad_department b
set dept_fullname=a.dept_fullname||'_'||b.dept_name
from ad_department as a
Where Length(b.dept_Code) = 6 And b.dept_Code Like '99%' and a.dept_id = b.parent_id;

这样可以

oracle这样貌似不行吧

什么标准？

作者: zhaoyh603 发布时间: 2011-02-15

看明白了吗？

作者: zhaoyh603 发布时间: 2011-02-15

子查询的款困惑

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