Question

我写了以下脚本

SELECT vil.account_id , 
       vil.imp_id, 
       vil.owner ,
       vil.start_date,
       CASE  
         WHEN ac.status = 4  
         THEN status_date  
         ELSE NULL  
       END AS Live_date,
       cs.country_code  
  FROM ACCOUNT ac  
  INNER JOIN vu_imp_list vil  
     ON vil.account_id = ac.account_id  
  INNER JOIN entity e  
     ON ac.entity_id = e.entity_id  
  INNER JOIN country_specifics cs  
     ON e.country_id = cs.country_id  
  WHERE (vil.account_id, vil.start_date) =   
        (SELECT vils.account_id, MIN(vils.start_date)   
           FROM vu_imp_list vils  
          WHERE vil.account_id IN  ('825808009','987323136')  
          group by vils.account_id);

但我一直收到错误

SQL Error: ORA-01427: single-row subquery returns more than one row  
01427. 00000 -  "single-row subquery returns more than one row"

我尝试将rownum = 1添加到子查询的where子句中，但似乎查询正在永远运行。我已经单独测试了子查询，并为每个account_id返回一行。此处的大多数类似问题都与insert和update问题有关，而不仅仅是查询。

Answer 1

您需要确保子查询正好返回1行（或0）。我想你想要这个：

  WHERE vil.start_date =   
        (SELECT MIN(vils.start_date)   
           FROM vu_imp_list vils  
          WHERE vils.account_id IN ('825808009','987323136')  
        );

或如果子查询返回2行或更多行并且您想要将IN与其中任何一行进行比较，请使用start_date：

  WHERE vil.start_date IN   
        (SELECT MIN(vils.start_date)   
           FROM vu_imp_list vils  
          WHERE vils.account_id IN ('825808009','987323136')
          GROUP BY vils.account_id 
        );

或者也许这样，如果你想要一个相关的子查询：

  WHERE vil.account_id IN ('825808009','987323136')
    AND vil.start_date =   
        (SELECT MIN(vils.start_date)   
           FROM vu_imp_list vils  
          WHERE vils.account_id = vil.account_id 
        );

Answer 2

如果您的表vu_imp_list同时显示825808009 987323136和account_id，那么这个内部查询：

(SELECT vils.account_id, MIN(vils.start_date)   
 FROM vu_imp_list vils  
 WHERE vil.account_id IN ('825808009','987323136')  
 group by vils.ob10_account_id)

将生成2行，每行2列。

麻烦的是，您无法在WHERE中执行多列相等检查：

WHERE (vil.account_id, vil.start_date) =   
    (SELECT vils.account_id, MIN(vils.start_date) ... )

单行子查询返回多行 - 无更新或插入

2 个答案: