Question

我有两个查询，每个返回一个结果，即一个数字

Select Count(*) as StockCountA from Table_A where dept='AAA'

结果

StockCountA 
550

Select Count(*) as StockCountB from Table_B where dept='BBB'

结果

StockCountB 
450

我希望将这两个结果加入一行记录，即

| StockCountA | StockCountB    
| 550         | 450

Answer 1

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

说明：您可以选择单个值作为select语句中的字段，因此您可以编写类似

的内容

select
  x.*,
  (select Value from Table_Y y) as ValueFromY
from
  Table_X x

这仅适用于scalar queries，这意味着子查询应该只有1列，最多1行。如果0行，ValueFromY将返回NULL并且超过1行，则查询将失败。

select的另一个特性（在SQL Server，MySQL和其他人中）是你可以只选择值而不指定一个表，如下所示：

Select
  3.14 as MoreOrLessPI

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

Answer 2

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
);

Answer 3

尝试以下SQL：

select (Select Count(*) as StockCountA from Table_A where dept='AAA')  StockCountA, 
       (Select Count(*) as StockCountB from Table_B where dept='BBB')  StockCountB

希望这有助于：）

Answer 4

虽然并非总是最佳做法，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'

如何将两个查询结果合并为一行？

4 个答案: