2.左连接查询写法 usingSystem;usingSystem.Linq;namespaceLINQTutorial {classProgram {staticvoidMain(string[] args) {//例子一:varquery =fromempinEmployee.GetAllEmployees() join addinAddress.GetAddress() on emp.AddressId equals add.ID into EmpAddGroupfromempaddinEmpAddGroup.DefaultIfEmpty()selectnew{...
2、左连接(LEFT JOIN) //Sql: SELECT g.GroupName,u.UserName FROM GroupName g LEFT JOIN User u ON g.Id = u.GroupId //Linq to Sql: from g in Groups join u in Users on g.Id equals u.GroupId into Grp from grp in Grp.DefaultIfEmpty() select new { GroupName=g.GroupName, UserName...
linq left join写法在LINQ中,左连接(left join)可以使用 `GroupJoin` 运算符或 `Join` 方法来实现。下面是两种写法的示例: 示例1:使用 `GroupJoin` 运算符 ```csharp var leftJoin = from left in leftTable join right in rightTable on left.Key equals right.Key into temp from right in temp....
right join Book as b on s.id=b.studentid 要用Linq实现左连接,写法如下 DataClasses1DataContext db = new DataClasses1DataContext(); var leftJoinSql = from student in db.Student join book in db.Book on student.ID equals book.StudentID into temp from tt in temp.DefaultIfEmpty() select new ...
Linq To Sql 实现三个表 LEFT JOIN 如下：var list = (from u in dc.userinfos join j in dc.jobs on u.job equals j.jid into j_join from x in j_join.DefaultIfEmpty()join c in dc.cities on u.city equals c.cid into c_join from v in c_join.DefaultIfEmpty()select new { id = u....
join s in DBContext.SPKC on new {k.SpxxId,k.Ckid} equals new {s.SPXXID,s.CKID} into g1 from gc1 in g1.DefaultIfEmpty()select new { ... ...};但是很不给⼒的是这样居然提⽰错误：The type arguments cannot be inferred from the query.简直就是杯具，难道LINQ不⽀持这样搞？唉...
Linq 多连接及 left join 实例 记录 var retList = from d in mbExList.Cast<MaterialBaseEx>().ToList() join c in umcList.Cast<ClassifyBaseEx>().ToList() on d.ClsCode equals c.ClsCode join b in collectItem.Cast<CollectItem>().ToList() on d.Guid equals b.MatID into temp...
这代码看的晕啊...一般 linq 连接用的是 from a in A jion b in B on ...条件 外连接用的是 from a in A jion b in B on ...条件 into C from a in C.DefaultIfEmpty()
RIGHTJOIN [Desc] ON Student.ID=[Desc].ID PS:A left join B=B right join A 对应linq以及lambda即调换两个表位置 inner join: SELECT * FROM Student INNER JOIN [Desc] ON Student.ID=[Desc].ID linq: 读取全部: from student in db.Student join desc in db.Desc on student.ID equals desc.Stu...
LINQ 框架中提供的 join 方法包括Join和GroupJoin。 这些方法执行同等联接,即根据 2 个数据源的键是否相等来匹配这 2 个数据源的联接。 (对于比较,Transact-SQL 支持equals运算符以外的 join 运算符,例如less than运算符)在关系数据库术语中,Join会实现内部 join,这是一种类型的 join,其中仅返回在其他数据集中...