如何在同一列上连接三种不同的类型

Question

我需要为下面的场景编写连接查询。我知道如果有表使用PRIMARY键而其他表将其定义为外键时如何编写联接。但这里的情况有所不同。请参阅表格的结构。

 ID      Type      UserId

 1       User         1              // Straight away defining User table
 2       Dept         10             // Defining Dept. so it should get all the users under the Dept Id(10)
 3       Route        100            // Defining Route. so it should get all the users from Route Id(100).

我不知道如何在LINQ中为这种情况编写连接查询。请给我一些建议。

我尝试了三组不同的查询，然后将这些结果作为单个列表加入。这是代码。

代码：

var usersWithDeptId = db.Users.Where(asd => asd.UserDeptId == Id).Select(asd => asd.Id);
var listUserValue = from cap in db.CareAllocationPercents
                    where cap.Type == 1 && UsersWithDeptId.Contains(cap.UserId)
                    select new UserWithDeptId
                    {
                         Year = db.CareAllocations.FirstOrDefault(amt => amt.CareItemId == cap.CareItemId).Year,
                         Amount = db.CareAllocations.FirstOrDefault(amt => amt.CareItemId == cap.CareItemId).Amount,
                         UserId = cap.UserId,
                         UserDeptId = db.Users.FirstOrDefault(userdept => userdept.Id == cap.UserId).UserDeptId,
                         Percentage = cap.Percentage,
                         CareItemId = cap.CareItemId,
                         Category = "User",
                         CareAllocationId = cap.Id
                    };
listUserValue = listUserValue.Where(asd => asd.Year == Year).ToList();

List<int> routeIds = db.CareAllocationPercents.Where(asd => asd.Type == 3).Select(asd => asd.UserId).ToList();
var UsersWithRoutingId = from route in db.RoutingListMembers
                         where RouteIds.Contains(route.RoutingListId.Value) && route.User.UserDeptId == Id
                         select new RoutingWithUser
                         {
                             UserId = route.UserId,
                             RoutingId = route.RoutingListId
                         };

var listRouteValue = from cap in db.CareAllocationPercents
                     where cap.Type == 3
                     select new UserWithDeptId
                     {
                          Year = db.CareAllocations.FirstOrDefault(amt => amt.CareItemId == cap.CareItemI).Year,
                          Amount = db.CareAllocations.FirstOrDefault(amt => amt.CareItemId == cap.CareItemI).Amount,
                          UserId = cap.UserId,
                          UserDeptId = db.Users.FirstOrDefault(userdept => userdept.Id == cap.UserId).UserDeptId,
                          Percentage = cap.Percentage,
                          Category = "Route",
                          CareItemId = cap.CareItemId,
                          CareAllocationId = cap.Id
                     };

List<UserWithDeptId> newRouteList = new List<UserWithDeptId>();
ListRouteValue = listRouteValue.Where(asd => asd.Year == Year).ToList();

foreach (var listdept in ListRouteValue)
{
    var user = UsersWithRoutingId.FirstOrDefault(uwri => uwri.RoutingId == listdept.UserId);
    if (user != null)
    {
        NewRouteList.Add(new UserWithDeptId
            {
                UserId = user.UserId,
                Year = listdept.Year,
                UserDeptId = db.Users.FirstOrDefault(asd => asd.Id == user.UserId).Select(asd => asd.UserDeptId),
                Percentage = listdept.Percentage,
                CareItemId = listdept.CareItemId,
                Amount = listdept.Amount,
                CareAllocationId = listdept.CareAllocationId,
                Category = listdept.Category });
    }
}

newRouteList = newRouteList.Where(asd => asd.UserDeptId == Id).ToList();
var listUserId = from user in db.Users
                 where user.UserDeptId == Id
                 select new UserWithDeptId
                 {
                      UserId = user.Id
                 };

var listDeptId = from cap in db.CareAllocationPercents
                 where cap.Type == 2 && cap.UserId == Id
                 select new UserWithDeptId
                 {
                      Year = db.CareAllocations.FirstOrDefault(amt => amt.CareItemId == cap.CareItemId).Year,
                      Amount = db.CareAllocations.FirstOrDefault(amt => amt.CareItemId == cap.CareItemId).Amount,
                      UserDeptId = cap.UserId,
                      Percentage = cap.Percentage,
                      Category = "Dept",
                      CareItemId = cap.CareItemId,
                      CareAllocationId = cap.Id,
                 };

listDeptId = listDeptId.Where(asd => asd.Year == Year).ToList();
List<UserWithDeptId> newList = new List<userWithDeptId>();

foreach (var listdept in listDeptId)
{
    foreach (var users in listUserId)
    {
        newList.Add(new UserWithDeptId
            {
                UserId = users.UserId,
                UserDeptId = listdept.UserDeptId,
                Percentage = listdept.Percentage,
                CareItemId = listdept.CareItemId,
                Amount = listdept.Amount,
                CareAllocationId = listdept.CareAllocationId,
                Category = listdept.Category
            });
    }
}
newList.AddRange(listUserValue);
newList.AddRange(newRouteList);