query - two different tables

Tamir Hazan

Hey!

I want to make join from two different tables (with no connection between them):

Parkinglot (parkingLotID, addressParkingLot, statusParkingLot)

PublicParking (publicParkingID, addressPublicParking, statusParking).

And I want to write a query that returns all the parkings that are available - based on their status (Parkinglot & PublicParking).

I've read that I need to do full outer join (make one big table) and only then I can write the query.

I need to write the query in linq.

I really need your help about this query and about the full outer join (if it's right)

TNX!

8 Replies

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Nilesh Shah8y ago
Hi,

it may not be possible entirely in LINQ only as the two classes are different.

in cases like this, we create a DTO which is a dummy like class with same or common properties.

e.g.
resultSet = (from p in parkingLots
                        where p.statusParkingLot == 1
                        select new CommonParkingLotDTO {
                            parkingLotID = p.parkingLotID,
                            addressParkingLot = p.addressParkingLot,
                            statusParkingLot = p.statusParkingLot
                        })
                        .Union(
                        from p in publicParkingLots
                        where p.statusParking == 1
                        select new CommonParkingLotDTO {
                            parkingLotID = p.publicParkingID,
                            addressParkingLot = p.addressPublicParking,
                            statusParkingLot = p.statusParking
                        }).ToList();
I have attached complete project too.

Please mark this answer as accepted if you found your answer now.
Tamir Hazan8y ago
pliz I need your help
Tamir Hazan8y ago
I'm really sorry but it still have problem ):

Nilesh Shah, I appreciate it a lot !!!
Nilesh Shah8y ago
var union =
(from p in Parkinglot select p).AsQueryable().Union
(from p in PublicParking select p);
Tamir Hazan8y ago
I'm sorry but I didnt understand :

try using

.AsQueryable()

before .Union()

appreciate it a lot
Nilesh Shah8y ago
try using

.AsQueryable()

before .Union()
Tamir Hazan8y ago
Thank you for the answer!!!

but it's not work on LINQPad :
Nilesh Shah8y ago
I don't think you need join here as there is no maching column at all

what you need is "Union" which will give you records from both tables together in a single result.

you can write union in LINQ like this:
var union =
  (from p in Parkinglot select p).Union
  (from p in PublicParking select p);
or if this doesn't work then try selecting in a DTO instead of p