废话不多说了,直接给大家贴代码了,具体代码如下所示:

  -- 交叉连接产生笛卡尔值 (X*Y)  SELECT *  FROM  Student      cross Join dbo.ClassInfo   --另外一种写法  SELECT *  FROM  Student , ClassInfo   -- 内连接 (Inner 可以省略)  SELECT *  FROM  Student      JOIN dbo.ClassInfo ON dbo.Student.Class = dbo.ClassInfo.ID;  -- Inner Join  SELECT *  FROM  Student      INNER JOIN dbo.ClassInfo ON dbo.Student.Class = dbo.ClassInfo.ID;     -- on 条件,通常是 主外键,但是不限于主外键     -- on 条件,允许有多个,而且可能是针对某个表的  SELECT *  FROM  Student      INNER JOIN dbo.ClassInfo ON dbo.Student.Class = dbo.ClassInfo.ID      AND dbo.Student.Class IN (1,2) -- 针对Student表增加查询条件  -- 不等于 (笛卡尔值减去 相等的值)  SELECT *  FROM  Student      INNER JOIN dbo.ClassInfo ON dbo.Student.Class <> dbo.ClassInfo.ID;  --自连接 从Class表中查询到Class所在的系  SELECT T1.* ,T2.ClassName FROM dbo.ClassInfo AS T1      INNER JOIN dbo.ClassInfo AS T2 ON T1.PID=T2.ID  -- Left Join  SELECT *  FROM  Student      Left JOIN dbo.ClassInfo ON dbo.Student.Class = dbo.ClassInfo.ID;  -- Right Join  SELECT *  FROM  Student      RIGHT  JOIN dbo.ClassInfo ON dbo.Student.Class = dbo.ClassInfo.ID;  -- 全外连接  SELECT *  FROM  Student      FULL OUTER JOIN dbo.ClassInfo ON dbo.Student.Class = dbo.ClassInfo.ID;  -- 外连接和内连接的区别是:  -- 内连接,on条件不符合的话,会过滤掉数据  -- 外连接,以保留表为主,on条件成立显示数据,否则显示NULL  --Union 纵向连接  SELECT StuID,StuName,StuEnName,StuAge,StuBirthday  FROM  Student WHERE StuID<=2  UNION  SELECT StuID,StuName,StuEnName,StuAge,StuBirthday  FROM dbo.Student WHERE StuID>2  --Union 去重复  SELECT StuSex  FROM  Student WHERE StuID<=2  UNION  SELECT StuSex  FROM dbo.Student WHERE StuID>2  --Union 显示全部  SELECT StuSex  FROM  Student WHERE StuID<=2  UNION ALL  SELECT StuSex  FROM dbo.Student WHERE StuID>2  --Except 差集,排除  SELECT StuID,StuName,StuEnName,StuAge,StuBirthday  FROM  Student  Except  SELECT StuID,StuName,StuEnName,StuAge,StuBirthday  FROM dbo.Student WHERE StuID<=2  --Intersect 交集  SELECT StuID,StuName,StuEnName,StuAge,StuBirthday  FROM  Student WHERE StuID>=2  Except  SELECT StuID,StuName,StuEnName,StuAge,StuBirthday  FROM dbo.Student WHERE StuID<=3

以上所述是小编给大家介绍的SQL Server 2012 多表连接查询功能实例代码,希望对大家有所帮助,如果大家有任何疑问欢迎给我留言,小编会及时回复大家的!

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