Oracle SQL将来自同一表的2个查询与2个不同列中的输出结合起来

Question

我正在使用Oracle SQL数据库。 我正在尝试将这两个查询合并到同一张表中的一个查询中：

select count(CustomerID) from Customers
where (City = 'Berlin' or City = 'London')
from Customers;

select count(CustomerID) from Customers
where (City = 'Mannheim' or City = 'Strasbourg')
from Customers;

我的输出想像是在两列上导出的：

| Berlin & London | Mannheim & Strasbourg |
|-----------------------------------------|
|        5        |         10            |

此处的db示例， https ://www.w3schools.com/sql/trysql.asp ? filename =trysql_op_in

我认为答案将是：

(select count(CustomerID) from Customers
where (City = 'Berlin' or City = 'London'))
union
(select count(CustomerID) from Customers
where (City = 'Marseille' or City = 'Tsawassen'));
union
(select count(CustomerID) from Customers
where (City = 'Strasbourg' or City = 'Madrid'));

仍在测试中...

最终通过使用这种情况完成了工作。 感谢所有参与的人！

SELECT
  COUNT(CASE
    WHEN  work_zone = 'AMBGI01' OR
          work_zone = 'AMBGI02' OR
          work_zone = 'AMBGI03' AND
          task_type = 'P' THEN work_zone
  END) "HighBay Putaways",
  COUNT(CASE
    WHEN  work_zone = 'AMBGI04' OR
          work_zone = 'AMBGI05' OR
          work_zone = 'AMBGI06' OR
          work_zone = 'AMBGI07' AND
          task_type = 'P' THEN work_zone
  END) "LowBay Putaways",
  COUNT(CASE
    WHEN  from_loc_id = 'THEWALL' AND
          task_type = 'P' THEN from_loc_id
    END) "THE WALL",
    COUNT(CASE
    WHEN  tag_id like '%' AND
          from_loc_id like 'EXPANS%' AND
           task_type = 'P' THEN tag_id
     END) "EXPANSION",
   COUNT(CASE
    WHEN  final_loc_id like '_______' AND
          (status = 'In Progress'        OR
          status = 'Released')          AND
          task_type = 'R' THEN final_loc_id
  END) "Replens"
FROM move_task;

Answer 1

尚不清楚您有两个表（ customers ， country ）还是一个。 如果有两个，则需要向我们展示结构。 w3schools.com说没有像country这样的表格， customers不包含store栏。 无论如何，您都需要条件count ，如下所示：

select count(case when city in ('Berlin', 'London')       
                  then 1 end) as "Berlin & London",
       count(case when city in ('Mannheim', 'Strasbourg') 
                  then 1 end) as "Mannheim & Strasbourg"
  from Customers
  where city in ('Berlin', 'London', 'Mannheim', 'Strasbourg')

您也可以使用pivot ，但这更简单，更易读，并且可以在较早的Oracle版本中使用。

Answer 2

最简单的方法如下：

select count(CASE WHEN City = 'Berlin' or City = 'London' THEN City END) "Berlin & London"
     , count(CASE WHEN City = 'Mannheim' or City = 'Strasbourg' THEN City END) "Mannheim & Strasbourg"
  from Customers