用实例展示left Join,right join,inner join,join,cross join,union 的区别
1.向TI,T2插入数据：
T1 7条
ID Field2 Field3 Field4
1 1 3 54
2 1 3 54
3 1 3 54
4 2 3 54
5 3 3 54
6 4 3 54
7 5 3 54
T2 7条
IDField22Field23
1133
2133
3133
4133
5233
6333
7 9 33
2.测试left join
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 left join dbo.T2 on t1.Field2=t2.Field22
row_numIDField2Field3Field4IDField22Field23
1113541133
2113542133
3113543133
4113544133
5213541133
6213542133
7213543133
8213544133
9313541133
10313542133
11313543133
12313544133
13423545233
14533546333
NULLNULLNULL
NULLNULLNULL
3.测试right join
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 right join dbo.T2 on t1.Field2=t2.Field22
row_numIDField2Field3Field4IDField22Field23
2113541133
3113542133
4113543133
5113544133
6213541133
7213542133
8213543133
9213544133
10313541133
11313542133
12313543133
13313544133
14423545233
15533546333
4.测试join
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 join dbo.T2 on t1.Field2=t2.Field22
row_numIDField2Field3Field4IDField22Field23
1113541133
2113542133
3113543133
4113544133
5213541133
6213542133
7213543133
8213544133
9313541133
10313542133
11313543133
12313544133
13423545233
14533546333
5.测试inner join
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 inner join dbo.T2 on t1.Field2=t2.Field22
row_numIDField2Field3Field4IDField22Field23
1113541133
2113542133
3113543133
4113544133
5213541133
6213542133
7213543133
8213544133
9313541133
10313542133
11313543133
12313544133
13423545233
14533546333
6.测试cross join
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 cross join dbo.T2 on t1.Field2=t2.Field22
消息156，级别15，状态1，第1 行
关键字'on' 附近有语法错误。
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 cross join dbo.T2
row_numIDField2Field3Field4IDField22Field23
1113541133
2113542133
3113543133
4113544133
5113545233
6113546333
7113548933
8213541133
9213542133
10213543133
11213544133
12213545233
13213546333
14213548933
15313541133
16313542133
17313543133
18313544133
19313545233
20313546333
21313548933
22423541133
23423542133
24423543133
25423544133
26423545233
27423546333
28423548933
29533541133
30533542133
31533543133
32533544133
33533545233
34533546333
35533548933
36643541133
37643542133
38643543133
39643544133
40643545233
41643546333
42643548933
43753541133
44753542133
45753543133
46753544133
47753545233
48753546333
49753548933
7.测试unoin
select * from dbo.T1 union all select * from dbo.T2
消息205，级别16，状态1，第1 行
使用UNION、INTERSECT 或EXCEPT 运算符合并的所有查询必须在其目标列表中有相同数目的表达式。
select Field2 from dbo.T1 union all select Field22 from dbo.T2
Field2
1
1
1
2
3
4
5
1
1
1
1
2
3
9
with T3 as
( select Field2 from dbo.T1 union all select Field22 from dbo.T2 )
select ROW_NUMBER() over (order by T3.field2) as row_num,* from T3
row_numField2
11
21
31
41
51
61
71
82
92
103
113
124
135
149
8.生成数据库的脚本
USE [Demo]
GO
/****** Object: Table [dbo].[T1] Script Date: 09/27/2013 23:19:29 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[T1](
) NOT NULL,
[Field2] [int] NULL,
[Field3] [int] NULL,
[Field4] [int] NULL,
CONSTRAINT [PK_T1] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
USE [Demo]
GO
/****** Object: Table [dbo].[T2] Script Date: 09/27/2013 23:19:53 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[T2](
) NOT NULL,
[Field22] [int] NOT NULL,
[Field23] [int] NOT NULL,
CONSTRAINT [PK_T2] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
delete from dbo.T1
truncate table dbo.T2
select * from T1
select * from T2
)
)
)
)
)
)
)
truncate table dbo.T2
)
)
)
)
)
)
)
)
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 left join dbo.T2 on t1.Field2=t2.Field22
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 right join dbo.T2 on t1.Field2=t2.Field22
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 join dbo.T2 on t1.Field2=t2.Field22
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 inner join dbo.T2 on t1.Field2=t2.Field22
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 cross join dbo.T2 on t1.Field2=t2.Field22
select ROW_NUMBER()over (order by t1.id,t2.id) as row_num,* from dbo.T1 cross join dbo.T2
select * from dbo.T1 union all select * from dbo.T2
select Field2 from dbo.T1 union all select Field22 from dbo.T2
with T3 as
( select Field2 from dbo.T1 union all select Field22 from dbo.T2 )
select ROW_NUMBER() over (order by T3.field2) as row_num,* from T3
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