1、左连接:

1、左连接:

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                        
};

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                        
};

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
};

2、右连接:

2、右连接:

 3、内连接:

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
};

var RightJoin = from dept in
ListOfDepartment
join employee in ListOfEmployees
on dept.ID equals employee.DeptID into joinDeptEmp
from employee in joinDeptEmp.DefaultIfEmpty()
必发娱乐官方网站,select new                          
{
EmployeeName = employee != null ? employee.Name : null,
DepartmentName = dept.Name
};

 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,

3、内连接:

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

 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,

                 select new TB_USER_ZYK
                 {
                    USER_ID
= t.USER_ID,
                    USER_NAME = t.USER_NAME,
                    USER_PASSWORD =
t.USER_PASSWORD,

                 };

                 };

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