将两个 SQL SELECT 查询结果合并为一个查询和一个结果

Question

我在合并两个选择查询的结果时遇到问题，
我在 sql 中执行了以下代码，您可以尝试

CREATE TABLE #a(a_id int, is_active bit, cr_date date)
CREATE TABLE #b(b_id int, a_id int, cr_date date)

INSERT INTO #a(a_id,is_active, cr_date)
VALUES(1,1,GETDATE()),(2,0,GETDATE()),(3,1,GETDATE()),(4,0,GETDATE()),(5,0,GETDATE())

INSERT INTO #b(b_id,a_id,cr_date)
VALUES(1,1,GETDATE()),(2,1,GETDATE()),(3,4,GETDATE()),(4,4,GETDATE()),(5,4,GETDATE()),(6,4,GETDATE())


CREATE TABLE #c(c_id int, is_active bit, cr_date date)
CREATE TABLE #d(d_id int, c_id int, cr_date date)

INSERT INTO #c(c_id,is_active, cr_date)
VALUES(1,1,GETDATE()),(2,0,GETDATE()),(3,1,GETDATE()),(4,0,GETDATE()),(5,0,GETDATE())

INSERT INTO #d(d_id,c_id,cr_date)
VALUES(1,1,GETDATE()),(2,1,GETDATE()),(3,4,GETDATE()),(4,4,GETDATE()),(5,4,GETDATE()),(6,4,GETDATE())



DECLARE @startDate date;
DECLARE @endDate date;
set @startDate='2012-10-26';
set @endDate=GETDATE();

SELECT 
'#b= '+CAST(COUNT(b.b_id) AS VARCHAR)   b_COUNT,
'#a = '+CAST(COUNT(a.a_id) AS VARCHAR)  a_COUNT  
FROM #a as a LEFT JOIN #b as b    ON a.a_id = b.a_id AND a.is_active = 0
WHERE CONVERT(VARCHAR(10), a.cr_date, 111)   BETWEEN @STARTDATE AND @ENDDATE

SELECT 
'#d= '+CAST(COUNT(d.d_id) AS VARCHAR)   d_COUNT,
'#c = '+CAST(COUNT(c.c_id) AS VARCHAR)  c_COUNT  
FROM #c as c LEFT JOIN #d as d    ON c.c_id = d.c_id AND c.is_active = 0
WHERE CONVERT(VARCHAR(10), c.cr_date, 111)   BETWEEN @STARTDATE AND @ENDDATE

for dropping tables 
DROP TABLE #a
DROP TABLE #b
DROP TABLE #c
DROP TABLE #d

我得到了两个选择查询的以下结果

现在，我想合并选择查询的两个结果，但我不能。

任何人都可以告诉我如何合并两个查询以获得输出中的单个结果

Answer 1

您可以使用UNION或UNION ALL。

例子：

SELECT N'A' as col
UNION ALL
SELECT N'B' as col

您可以使用ALL将结果保留原样。即使可能有重复。ALL会更快。

如果您遗漏了ALL查询，系统将检查是否有重复项。