单行子查询返回多行

[he1hehe]

今天这个sql语句报了一个单行子查询返回多行的错误

select t.*， 
       (select t_evolve_weekevolve
         from t_mk_mission
         where t_evolve_id = t.t_plan_id
           and t_evolve_week = t.t_plan_week
           and t_sys_flag <> -1) as weekevolve
  from T_MK_PLAN t
 where t.t_plan_submitflag <> 0
   and t.t_plan_week = 4
   and t.t_plan_deptid = 48000147100
   and t.T_PLAN_YEAR = 2011
   and t.t_sys_flag <> -1
 order by t.t_plan_id desc

从网上查了一下，看到一个例子
select 名字，姓氏 from 雇员 where 薪金 = （select 薪金 from 雇员 where 部门标识 =20）;
这个例子看懂了，但是上面那个是怎么回事？求高手指教。

[youshang444]

select t_evolve_weekevolve
         from t_mk_mission
         where t_evolve_id = t.t_plan_id
           and t_evolve_week = t.t_plan_week
           and t_sys_flag <> -1

这一条语句返回了多条记录

[不要悲剧人生]

根据你的条件T_MK_PLAN 表中的一条数据，在 t_mk_mission表中有多条数据对应。

[我心飞翔]

(select t_evolve_weekevolve
from t_mk_mission
where t_evolve_id = t.t_plan_id
and t_evolve_week = t.t_plan_week
and t_sys_flag <> -1)

这个子查询返回了多个结果（即有多条记录满足当前的查询条件），就会出现上述错误。
如果该返回结果，只有一条记录，则不会出现错误。

[开着拖拉机泡妞]

select t.*，
(select t_evolve_weekevolve
from t_mk_mission
where t_evolve_id = t.t_plan_id
and t_evolve_week = t.t_plan_week
and t_sys_flag <> -1) as weekevolve--把这个查询语句的结果作为一个新的列，取名weekevolve
from T_MK_PLAN t
where t.t_plan_submitflag <> 0
and t.t_plan_week = 4
and t.t_plan_deptid = 48000147100
and t.T_PLAN_YEAR = 2011
and t.t_sys_flag <> -1
order by t.t_plan_id desc

[开着拖拉机泡妞]

select t.*，--查询 T_MK_PLAN 表（别名t）里的所有字段
(select t_evolve_weekevolve
from t_mk_mission
where t_evolve_id = t.t_plan_id
and t_evolve_week = t.t_plan_week
and t_sys_flag <> -1) as weekevolve--把这个查询语句的结果作为一个新的列，取名weekevolve
from T_MK_PLAN t
where t.t_plan_submitflag <> 0
and t.t_plan_week = 4
and t.t_plan_deptid = 48000147100
and t.T_PLAN_YEAR = 2011
and t.t_sys_flag <> -1
order by t.t_plan_id desc

[Rotel-刘志东]

具体要把条件限制一下了。

[宋哥]

[Quote=引用 5 楼 travylee 的回复:]
select t.*，--查询 T_MK_PLAN 表（别名t）里的所有字段
(select t_evolve_weekevolve
from t_mk_mission
where t_evolve_id = t.t_plan_id
and t_evolve_week = t.t_plan_week
and t_sys_flag <> -1) as weekevolve--把这个查询……
[/Quote]
这个注解很好，可在子查询中加条件限制，保证只有一行，就不会报错了，例如：

select t.*， 
       (select t_evolve_weekevolve
         from t_mk_mission
         where t_evolve_id = t.t_plan_id
           and t_evolve_week = t.t_plan_week
           and t_sys_flag <> -1 and rownum=1 ) as weekevolve
  from T_MK_PLAN t
 where t.t_plan_submitflag <> 0
   and t.t_plan_week = 4
   and t.t_plan_deptid = 48000147100
   and t.T_PLAN_YEAR = 2011
   and t.t_sys_flag <> -1
 order by t.t_plan_id desc

[大明湖畔_帅锅]

能上几行数据看看么

[争取今天]

这种情况有可能是数据问题,除了异常.先检查数据是否合法.

如果合法,只能修改语句了

[he1hehe]

不明白，把t.t_plan_week = 4换成t.t_plan_week = 6就没问题了？

[he1hehe]

不明白，把t.t_plan_week = 4换成t.t_plan_week = 6就没问题了

select t_evolve_weekevolve
         from t_mk_mission
         where t_evolve_id = t.t_plan_id
           and t_evolve_week = t.t_plan_week
           and t_sys_flag <> -1

这个子查询也是返回多行，但是整个sql就能执行了，能查询出结果了。

[he1hehe]

哦，明白了，是数据有问题。