C# SQL无法插入附加条件

下面是我的SQL查询：

var staffLeaves = (from staffLeave in db.StaffLeaves
                   join leavetype in db.LeaveTypes
                   on staffLeave.LeaveID equals leavetype.LeaveTypeID

                   join staff in db.Staffs
                   on staffLeave.StaffID equals staff.StaffID
                   where staffLeave.Year == latest_year.Year

                   //new insertion start

                   join jobinfo in db.JobInfo
                   on staffLeave.StaffID equals jobinfo.staff_id
                   where jobinfo.last_date == null
         error --> OR jobinfo.last_date > DateTime.Now

                   //new insertion end

                   orderby leavetype.Description ascending

                   select new { staffLeave = staffLeave, staff = staff, leavetype = leavetype }).AsQueryable();

我可以知道如何添加附加条件

或jobinfo.last_date>DateTime.Now

或者我是否需要使用相同的表实现另一个

join

语句，但这次使用第二个条件

我正在使用SQL Server Management Studio 2014

多谢各位

var staffLeaves = (from staffLeave in db.StaffLeaves
               join leavetype in db.LeaveTypes
               on staffLeave.LeaveID equals leavetype.LeaveTypeID

               join staff in db.Staffs
               on staffLeave.StaffID equals staff.StaffID
               where staffLeave.Year == latest_year.Year

               //new insertion start

               join jobinfo in db.JobInfo
               on (staffLeave.StaffID equals jobinfo.staff_id and jobinfo.last_date == null and jobinfo.last_date > DateTime.Now)


               //new insertion end

               orderby leavetype.Description ascending

               select new { staffLeave = staffLeave, staff = staff, leavetype = leavetype }).AsQueryable(); 

所以我在连接中添加了where条件

试试这个：

var staffLeaves = (from staffLeave in db.StaffLeaves
                   from leavetype in db.LeaveTypes
                   from staff in db.Staffs
                   from jobinfo in db.JobInfo
                   where staffLeave.LeaveID == leavetype.LeaveTypeID && 
                   staffLeave.LeaveID == leavetype.LeaveTypeID && 
                   staffLeave.Year == latest_year.Year &&
                   staffLeave.StaffID == jobinfo.staff_id &&
                   (jobinfo.last_date == null || jobinfo.last_date > DateTime.Now)
                   orderby leavetype.Description ascending
                   select new { staffLeave = staffLeave, staff = staff, leavetype = leavetype }).AsQueryable();

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请。添加您的数据库名称，如SQL SERVER、ORACLE、MYSQL等，我会将其添加进去