通过表达式与oracle中的case语句进行分组？

问题描述

我有一个带有case语句的查询。

select
   COUNTRY_CODE,CUST_USR_ID,(
      case
         when
            FACILITY_ID is not null 
         then
            FACILITY_ID 
         when
            ACCOUNT_NO is not null 
         then
            ACCOUNT_CLASS 
      end
   )
   ACC_FA_ID,count(1),(
      case
         when
            FACILITY_ID is not null 
         then
            'FACILITY_ID' 
         else
            'ACCOUNT_CLASS' 
      end
   )
   IDENTIFIERS 
from
   Mytable 
where
   (
      FACILITY_ID is not null 
      or ACCOUNT_NO is not null
   )
group by
   COUNTRY_CODE,(
      case
         when
            FACILITY_ID is not null 
         then
            FACILITY_ID 
         when
            ACCOUNT_NO is not null 
         then
            ACCOUNT_CLASS 
      end
   )

此查询给我错误

ORA-00979：不是GROUP BY表达式

当我从select中删除我的最后一个case语句时，它运行良好。请帮助我

解决方法

未聚合的列应成为GROUP BY子句的一部分。表示“解决方案”

• 不是从CASE中删除第二个SELECT，而是
• 将其添加到GROUP BY

这样的事情（CTE在这里只是为了提供一些示例数据以显示查询起作用；它是否产生了您想要的含义，我无法告诉）：

SQL> WITH mytable (
  2    country_code,cust_usr_id,facility_id,account_no,account_class
  3  ) AS
  4  (SELECT 1,1,1 FROM dual UNION ALL
  5   SELECT 1,2,3,4,5 FROM DUAL
  6  )
  7  SELECT country_code,8         cust_usr_id,9         CASE
 10           WHEN facility_id IS NOT NULL THEN
 11             facility_id
 12           WHEN account_no IS NOT NULL THEN
 13             account_class
 14         END acc_fa_id,15         COUNT(1),16        --
 17         CASE
 18           WHEN facility_id IS NOT NULL THEN
 19             'FACILITY_ID'
 20           ELSE
 21             'ACCOUNT_CLASS'
 22         END identifiers
 23  FROM mytable
 24  WHERE (   facility_id IS NOT NULL
 25         OR account_no  IS NOT NULL)
 26  GROUP BY country_code,27           cust_usr_id,28           CASE
 29             WHEN facility_id IS NOT NULL THEN
 30               facility_id
 31             WHEN account_no IS NOT NULL THEN
 32               account_class
 33           END,34           CASE
 35             WHEN facility_id IS NOT NULL THEN
 36               'FACILITY_ID'
 37             ELSE
 38               'ACCOUNT_CLASS'
 39           END;

COUNTRY_CODE CUST_USR_ID  ACC_FA_ID   COUNT(1) IDENTIFIERS
------------ ----------- ---------- ---------- -------------
           1           2          3          1 FACILITY_ID
           1           1          1          1 FACILITY_ID

SQL>