单例选择SQL多行

Question

我有以下SQL：

WITH G1 AS 
(SELECT G.NUM_REFE, G.GUIA AS MASTER, 
        (SELECT H.GUIA FROM SAAIO_GUIAS H WHERE G.NUM_REFE = H.NUM_REFE AND H.IDE_MH ="H" AND H.CONS_GUIA="1" ) AS HOUSE
FROM SAAIO_GUIAS G WHERE G.IDE_MH ="M" AND G.CONS_GUIA ="1" )
SELECT
*
FROM G1

并返回错误

  

＆＃34; Singleton Select中的多行＆＃34;。

这是数据库的样本

任何提示都将深受赞赏

由于

Answer 1

问题出在CTE SELECT子查询中。

我认为您可以使用CASE express代替SELECT Subquery

WITH G1 AS 
(
select
  num_refe,
  Case when ide_mh = 'M' then GUIA ELSE '' END as MASTER,
  Case when ide_mh = 'H' then GUIA ELSE '' END as HOUSE
from saaio_guias
where cons_guia = 1 
)
SELECT
*
FROM G1

OR

SELECT G.NUM_REFE, G.GUIA AS MASTER,H.GUIA
FROM SAAIO_GUIAS G 
INNER JOIN 
(
    SELECT * 
    FROM SAAIO_GUIAS
    WHERE IDE_MH ='H'  AND CONS_GUIA='1'
) AS H ON  G.NUM_REFE = H.NUM_REFE
WHERE G.IDE_MH ='M' AND G.CONS_GUIA ='1'

我不知道你期望的结果是什么。所以我猜这两个问题对你有帮助。

Answer 2

您的查询想要检索匹配GUIA的一个，但似乎NUM_REFE每个IDE_MH = 'H' AND CONS_GUIA = 1可能有多个条目。用

检查

select num_refe
from saaio_guias
where ide_mh = 'H'
  and cons_guia = 1
group by num_refe
having count(*) > 1;

这应该没有结果，但它可能会。如果确实如此，则它无法用于您的查询，您必须考虑在这种情况下要选择哪个值。也许只是最小或最大：

(
  select min(h.guia)
  from saaio_guias h
  ...

或者您可能希望从表中删除您认为重复的行并添加约束（num_refe + ide_mh + cons_guia上的唯一索引）以防止将来出现此类记录。

顺便使用条件聚合可以简化您的查询：

select
  num_refe,
  any_value(case when ide_mh = 'M' then guia end) as master,
  any_value(case when ide_mh = 'H' then guia end) as guia
from saaio_guias
where cons_guia = 1
group by num_refe
order by num_refe;