Oracle / SQL - 合并来自“不相关”的无关表的计数 [英] Oracle/SQL - Combining counts from 'unrelated' unrelated tables

问题描述

让我们假设我存储了用于生成窗口小部件的记录的两个表 GOOD 和 BAD 。我的表格如下

Let's assume I two tables GOOD and BAD that stores records for widget production. My tables look like this

Widget      Good
----------------
Widget A    Y
Widget A    Y
Widget B    Y

Widget      Bad
----------------
Widget A    Y
Widget B    Y

我有这两个基本查询

select count(*) as good from table_good where widget = 'Widget A' and Good = 'Y'
select count(*) as bad from table_bad where widget = 'Widget A' and Bad = 'Y'

在这样的两个表中

good
----
2

bad
---
1

单个查询，其中我将返回一个具有单个记录的表格，如下所示

I would like to combine these into a single query where I would get back a table with a single record that looks like this

good    bad
-----------
2       1

做这个。我认为做一个联合和在其他表中设置假列选择会做到，但我得到了正确的表模式，但有两个单独的记录。

Can someone point me how to do this. I thought doing a union and setting up fake columns in the other tables selects would do it, but I got the right table schema back, but had two seperate records.

谢谢！

推荐答案

尝试：

SELECT (SELECT COUNT(*) AS good 
        FROM   table_good 
        WHERE  widget = 'Widget A' 
               AND good = 'Y') AS good, 
       (SELECT COUNT(*) AS bad 
        FROM   table_bad 
        WHERE  widget = 'Widget A' 
               AND bad = 'Y')  AS bad 
FROM   dual  

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