SQL 如何将两个查询的结果合并为一行？
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How to combine two query's results into one row?
提问by Rosebud
I have two queries that return one result each i.e one number
我有两个查询，每个查询返回一个结果，即一个数字
Select Count(*) as StockCountA from Table_A where dept='AAA'
Results
结果
StockCountA
550
.
.
Select Count(*) as StockCountB from Table_B where dept='BBB'
Results
结果
StockCountB
450
I wish to join the two results into one row record i.e
我希望将两个结果合并为一行记录，即
| StockCountA | StockCountB
| 550 | 450
回答by GolezTrol
You can use:
您可以使用：
select
(Select Count(*) as StockCountA from Table_A where dept='AAA') as StockCountA,
(Select Count(*) as StockCountB from Table_B where dept='BBB') as StockCountB
Explanation: you can select single value as a field in a select statement, so you could write something like
说明：您可以在 select 语句中选择单个值作为字段，因此您可以编写类似
select
x.*,
(select Value from Table_Y y) as ValueFromY
from
Table_X x
This will work only with scalarqueries, meaning that the sub-query should have exactly 1 column, and at most 1 row. With 0 rows ValueFromY will return NULLand with more than 1 row, the query will fail.
这仅适用于标量查询，这意味着子查询应该正好有 1 列，最多 1 行。ValueFromY 将返回 0 行NULL，超过 1 行，查询将失败。
An additional feature of select(in SQL Server, MySQL and probably others) is that you can select just values without specifying a table at all, like this:
select（在 SQL Server、MySQL 和其他可能的情况下）的附加功能是您可以只选择值而不指定表，如下所示：
Select
3.14 as MoreOrLessPI
You can combine both those facts to combine the two counts into a single result, by writing a query that looks like:
通过编写如下所示的查询，您可以将这两个事实结合起来，将这两个计数合并为一个结果：
Select
(Select query that returns at most 1 row) as Result1,
(Select another query that returns at most 1 row) as Result2
回答by Darshan Mehta
This should give you the desired result:
这应该会给你想要的结果：
SELECT * FROM(
(Select Count(*) as StockCountA from Table_A where dept='AAA') StockCountA ,
(Select Count(*) as StockCountB from Table_B where dept='BBB') StockCountB
);
回答by Leptonator
While not always the best practice, it is possible to do a CROSS JOIN..
虽然并不总是最佳实践，但可以进行 CROSS JOIN..
SELECT
COUNT(Table_A.SOME_COLUMN) as StockCountA
,COUNT(Table_B.SOME_COLUMN) as StockCountB
FROM Table_A, Table_B WHERE Table_A.dept='AAA' AND Table_B.dept='BBB'
回答by Hemant Patel
Try below SQL :
试试下面的 SQL ：
select (Select Count(*) as StockCountA from Table_A where dept='AAA') StockCountA,
(Select Count(*) as StockCountB from Table_B where dept='BBB') StockCountB
Hope This Helps :)
希望这可以帮助 ：）
