CODEWITHSUNDEEP
c#sqllinq
Red Taz
Red Taz

Reputation: 4179

LINQ LEFT JOIN, Combine multiple WHERE clauses with OR

LINQ,

var clause = PredicateBuilder.False<User>();
clause = clause.Or(u => u.uid.Equals(1));
clause = clause.Or(u => u.uid.Equals(2));

var usersInGroup = (from u in db.Users
                    join g in db.GroupUsers
                        on u.uid equals g.uid
                        into ug
                    from g in ug.DefaultIfEmpty()
                    where g.gid.Equals(0)
                    select u).Where(clause);

These two where clauses are chained together as;

WHERE ([t0].[gid] = 0) AND (([t1].[uid] = 1) OR ([t1].[uid] = 2))

 

How do I add the two where conditions as

WHERE ([t0].[gid] = 0) OR (([t1].[uid] = 1) OR ([t1].[uid] = 2))

Upvotes: 2

Views: 2067

Answers (3)

Jim Wooley
Jim Wooley

Reputation: 10408

Instead of doing multiple Or clauses, why not just do Contains. That way your list of Ids can be complete dynamic (as long as it doesn't exceed 2000):

var ids = new int[] {1, 2, 3}; 

var usersInGroup = (from u in db.Users 
                    join g in db.GroupUsers 
                        on u.uid equals g.uid 
                        into ug 
                    from g in ug.DefaultIfEmpty() 
                    where g.gid.Equals(0) 
                      && ids.Contains(u.uid)
                    select u);

Upvotes: 0

Red Taz
Red Taz

Reputation: 4179

Thanks to,

Can PredicateBuilder generate predicates that span multiple tables?

I now have a solution that works but my result set is based on a new hybrid class. As a result I have had to mirror all of the relevant fields. See below.

public class HybridGroupUser {
    private User _user;
    public User User {
        get { return _user; }
        set {
            _user = value;
            if (value != null) {
                uid = value.uid;
                fname = value.fname;
                lname = value.lname;
                email = value.email;
            }
        }
    }
    private GroupUser _GroupUser;
    public GroupUser GroupUser {
        get { return _GroupUser; }
        set {
            _GroupUser = value;
            if (value != null) {
                uid = value.uid;
                fname = value.fname;
                lname = value.lname;
                email = value.email;
            }
        }
    }

    public int? uid { get; set; }
    public string fname { get; set; }
    public string lname { get; set; }
    public string email { get; set; }
}

With this class I can now do the following;

var clause = PredicateBuilder.False<HybridGroupUser>();

clause = clause.Or(u => u.GroupUser.gid.Equals(0);
foreach (int i in AddedUsers) {
    int tmp = i;
    clause = clause.Or(u => u.User.uid.Equals(tmp));
}

var usersInGroup = (from u in db.Users
                    join gusr in db.GroupUser
                        on u.uid equals gusr.uid
                        into ug
                    from gusr in ug.DefaultIfEmpty()
                    select new HybridGroupUser {
                       User = u, 
                       GroupUser = gusr
                    }).Where(clause);

Upvotes: 2

esastincy
esastincy

Reputation: 1627

var usersInGroup = (from u in db.Users
join g in db.Groups
on u.uid equals g.uid
where g.gid.Equals(0) || (u.uid.Equals(1) || u.uid.Equals(2))
select u)

Upvotes: 0

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