1.左连接: var LeftJoin = from t1 in l1join t2 in l2on t1.ID equals t2.ID into Joinedt12from t3 in Joinedt12.DefaultIfEmpty()select new {Name = t1.Name,Age=t2.Age }; 2.右连接: var RightJoin = from t2 in l2join t
内连接查询 内连接与SqL中inner join一样,即找出两个序列的交集 Model1Container model = new Model1Container(); //内连接 var query = from s in model.Student join c in model.Course on s.CourseCno equals c.Cno select new { ClassID = s.CourseCno, ClassName = c.Cname, Student = new {
SELECT * FROM Table_A GO SELECT * FROM Table_B GO --内连接 SELECT a.*, b.* FROM Table_A a JOIN Table_B b ON a.ID = b.ID SELECT a.*, b.* FROM Table_A a INNER JOIN Table_B b ON a.ID = b.ID GO --内连接等价直接多表from的形式 SELECT a.*, b.* FROM Table_A a INNER JOIN Ta
表结构见前面博客 1.内连接 1.1.等值连接:在连接条件中使用等于号(=)运算符比较被连接列的列值,其查询结果中列出被连接表中的所有列,包括其中的重复列. 三种写法: select * from t_fn_person a , t_fn_dept b where a.dept_id=b.dept_id; select * from t_fn_person a join t_fn_dept b on a.dept_id=b.dept_id; select * from t_fn_person a
关于自连接.左外连接.右外连接.全连接: 简单来讲,随便来个例子: A表 B表 id name id name 1 a 1 b 2 b 3 c 4 c 内连接就是左表和右表相同的数据: select * from A inner join B on A.id=B.id id name id name 1 a 1 b 外连接分为:左外连接.右外连接.全外连接 左外连接就是以左表为准,去匹配右表,左表有多少条数据,结果就是多少条数据 select * from A left jo