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详细介绍SQL交叉表的实例


  很简单的一个东西,见网上好多朋友问“怎么实现交叉表?”,以下是我写的一个例子,数据库基于SQL SERVER 2000。
  
  交叉表实例
  
  建表:
  
  在查询分析器里运行:
  
  CREATE TABLE [Test] (
  
  [id] [int] IDENTITY (1, 1) NOT NULL ,
  
  [name] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
  
  [subject] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
  
  [Source] [numeric](18, 0) NULL
  
  ) ON [PRIMARY]
  
  GO
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'张三',N'语文',60)
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'李四',N'数学',70)
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'王五',N'英语',80)
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'王五',N'数学',75)
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'王五',N'语文',57)
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'李四',N'语文',80)
  
  INSERT INTO [test] ([name],[subject],[Source]) values (N'张三',N'英语',100)
  
  Go
  
 

  交叉表语句的实现:
  
  用于:交叉表的列数是确定的
  
  select name,sum(case subject when '数学' then source else 0 end) as '数学',
  
  sum(case subject when '英语' then source else 0 end) as '英语',
  
  sum(case subject when '语文' then source else 0 end) as '语文'
  
  from test
  
  group by name
  
  --用于:交叉表的列数是不确定的
  
  declare @sql varchar(8000)
  
  set @sql = 'select name,'
  
  select @sql = @sql + 'sum(case subject when '''+subject+'''
  
  then source else 0 end) as '''+subject+''','
  
  from (select distinct subject from test) as a
  
  select @sql = left(@sql,len(@sql)-1) + ' from test group by name'
  
  exec(@sql)
  
  go
  
  运行结果:
  

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