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select * from t1 cross join t2

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select * from t1 cross join t2;--常用写法

select * from t1, t2;-- SQL:1989的规范

select * from t1 cross join t2

where t1.col1=t2.col2;--等价于内部联接

select * from t1 inner join t2  on t1.col1=t2.col2

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-- 员工表

CREATE TABLE [dbo].[EmpInfo](

  [empId] [int] IDENTITY(1,1) NOT NULL,

  [empNo] [varchar](20) NULL,

  [empName] [nvarchar](20) NULL,

 CONSTRAINT [PK_EmpInfo] PRIMARY KEY CLUSTERED 

(

  [empId] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF

, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]

-- 奖金表

CREATE TABLE [dbo].[SalaryInfo](

  [id] [int] IDENTITY(1,1) NOT NULL,

  [empId] [int] NULL,

  [salary] [decimal](18, 2) NULL,

  [seasons] [varchar](20) NULL,

 CONSTRAINT [PK_SalaryInfo] 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]

-- 季度表

CREATE TABLE [dbo].[Seasons](

  [name] [nchar](10) NULL

) ON [PRIMARY]

GO

SET IDENTITY_INSERT [dbo].[EmpInfo] ON

INSERT [dbo].[EmpInfo] ([empId], [empNo], [empName]) VALUES (1, N'A001', N'王强')

INSERT [dbo].[EmpInfo] ([empId], [empNo], [empName]) VALUES (2, N'A002', N'李明')

INSERT [dbo].[EmpInfo] ([empId], [empNo], [empName]) VALUES (3, N'A003', N'张三')

INSERT [dbo].[SalaryInfo] ([id], [empId], [salary], [seasons])

 VALUES (1, 1, CAST(3000.00 AS Decimal(18, 2)), N'第一季度')

INSERT [dbo].[SalaryInfo] ([id], [empId], [salary], [seasons])

 VALUES (2, 3, CAST(5000.00 AS Decimal(18, 2)), N'第一季度')

INSERT [dbo].[SalaryInfo] ([id], [empId], [salary], [seasons])

 VALUES (3, 1, CAST(3500.00 AS Decimal(18, 2)), N'第二季度')

INSERT [dbo].[SalaryInfo] ([id], [empId], [salary], [seasons])

 VALUES (4, 3, CAST(3000.00 AS Decimal(18, 2)), N'第二季度 ')

INSERT [dbo].[SalaryInfo] ([id], [empId], [salary], [seasons])

 VALUES (5, 2, CAST(4500.00 AS Decimal(18, 2)), N'第二季度')

INSERT [dbo].[Seasons] ([name]) VALUES (N'第一季度')

INSERT [dbo].[Seasons] ([name]) VALUES (N'第二季度')

INSERT [dbo].[Seasons] ([name]) VALUES (N'第三季度')

INSERT [dbo].[Seasons] ([name]) VALUES (N'第四季度')

-- 查询每个人每个季度的奖金情况 如果奖金不存在则为0

SELECT a.empName,b.name seasons ,isnull(c.salary,0) salary 

FROM EmpInfo a 

CROSS JOIN Seasons b

LEFT OUTER JOIN SalaryInfo c ON a.empId=c.empId AND b.name=c.seasons