Elegant linq solution for left joins with unique data - asp.net-mvc

Question

I woud like to inquire if my Linq solution below is a good solution or if there is a better way. I am new to using Linq, and am most familiar with MySQL. So I've been converting one of my past projects from PHP to .NET MVC and am trying to learn Linq. I would like to find out if there is a better solution than the one I came up with.
I have the following table structures:
CREATE TABLE maplocations (
ID int NOT NULL AUTO_INCREMENT,
name varchar(35) NOT NULL,
Lat double NOT NULL,
Lng double NOT NULL,
PRIMARY KEY (ID),
UNIQUE KEY name (name)
);
CREATE TABLE reservations (
ID INT NOT NULL AUTO_INCREMENT,
loc_ID INT NOT NULL,
resDate DATE NOT NULL,
user_ID INT NOT NULL,
PRIMARY KEY (ID),
UNIQUE KEY one_per (loc_ID, resDate),
FOREIGN KEY (user_ID) REFERENCES Users (ID),
FOREIGN KEY (loc_ID) REFERENCES MapLocations (ID)
);
CREATE TABLE Users (
ID INT NOT NULL AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
email VARCHAR(50) NOT NULL,
pass VARCHAR(128) NOT NULL,
salt VARCHAR(5) NOT NULL,
PRIMARY KEY (ID),
UNIQUE KEY unique_names (name),
UNIQUE KEY unique_email (email)
);
In MySQL, I use the following query to get the ealiest reservation at each maplocation with a non null date for any locations that don't have a reservation.
SELECT locs.*, if(res.resDate,res.resDate,'0001-01-01') as resDate, res.Name as User
FROM MapLocations locs
LEFT JOIN (
SELECT loc_ID, resDate, Name
FROM Reservations, Users
WHERE resDate >= Date(Now())
AND user_ID = Users.ID
ORDER BY resDate
) res on locs.ID = res.loc_ID
group by locs.ID
ORDER BY locs.Name;
In Linq, with Visual studio automatically creating much of the structure after connecting to the database, I have come up with the following equivalent to that SQL Query
var resList = (from res in Reservations
where res.ResDate >= DateTime.Today
select res);
var locAndRes =
(from loc in Maplocations
join res in resList on loc.ID equals res.Loc_ID into join1
from res2 in join1.DefaultIfEmpty()
join usr in Users on res2.User_ID equals usr.ID into join2
from usr2 in join2.DefaultIfEmpty()
orderby loc.ID,res2.ResDate
select new {
ID = (int)loc.ID,
Name = (string)loc.Name,
Lat = (double)loc.Lat,
Lng = (double)loc.Lng,
resDate = res2 != null ?(DateTime)res2.ResDate : DateTime.MinValue,
user = usr2 != null ? usr2.Name : null
}).GroupBy(a => a.ID).Select(b => b.FirstOrDefault());
So, I'm wondering is there a better way to perform this query?
Are these equivalent?
Are there any good practices I should be following?
Also, one more question, I'm having trouble getting this from the var to a List. doing something like this doesn't work
List<locAndResModel> locList = locAndRes.AsQueryable().ToList<locAndResModel>();
In the above snippet locAndResModel is just a class which has variables to match the int, string, double double, DateTime, string results of the query. Is there an easy way to get a list without having to do a foreach and passing the results to a constructor override? Or should I just add it to ViewData and return the View?

Answer 1

You'll want to take advantage of the automatic joins performed by the Entity Framework. Give this a try and let me know if it does what you want:
var locAndRes = from maplocation in MapLocations
let earliestReservationDate = maplocation.Reservations.Min(res => res.resDate)
let earliestReservation = (from reservation in mapLocation.Reservations
where reservation.resDate == earliestReservationDate && reservation.resDate >= DateTime.Today
select reservation).FirstOrDefault()
select new locAndResModel( maplocation.ID, maplocation.name, maplocation.Lat, maplocation.Lng, earliestReservation != null ? earliestReservation.resDate : DateTime.MinValue, earliestReservation != null ?earliestReservation.User.name : null)