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  • LINQ的左连接、右连接、内连接

    1、左连接:
    var LeftJoin = from emp in ListOfEmployees
    join dept in ListOfDepartment
    on emp.DeptID equals dept.ID into JoinedEmpDept
    from dept in JoinedEmpDept.DefaultIfEmpty()
    select new                        
    {
    EmployeeName = emp.Name,
    DepartmentName = dept != null ? dept.Name : null                        
    };
     
    2、右连接:
    var RightJoin = from dept in ListOfDepartment
    join employee in ListOfEmployees
    on dept.ID equals employee.DeptID into joinDeptEmp
    from employee in joinDeptEmp.DefaultIfEmpty()
    select new                          
    {
    EmployeeName = employee != null ? employee.Name : null,
    DepartmentName = dept.Name
    };
     
    3、内连接:
     var query = from t in entitiy.TB_GCGL_ADA_USER
                     join p in entitiy.TB_GCGL_ZY_ZYK
                     on t.ETPRS_CODE equals p.ETPRS_CODE
                     select new TB_USER_ZYK
                     {
                        USER_ID = t.USER_ID,
                        USER_NAME = t.USER_NAME,
                        USER_PASSWORD = t.USER_PASSWORD,
                     };

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  • 原文地址:https://www.cnblogs.com/netcs/p/11209233.html
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