How do you perform a CROSS JOIN with LINQ to SQL?
C#LinqLinq to-SqlCross JoinC# Problem Overview
How do you perform a CROSS JOIN with LINQ to SQL?
C# Solutions
Solution 1 - C#
A cross-join is simply the Cartesian product of two sets. There's no explicit join operator for it.
var combo = from p in people from c in cars select new { p.Name, c.Make, c.Model, c.Colour };
Solution 2 - C#
The same thing with the Linq extension method SelectMany
(lambda syntax):
var names = new string[] { "Ana", "Raz", "John" };
var numbers = new int[] { 1, 2, 3 };
var newList=names.SelectMany(
x => numbers,
(y, z) => { return y + z + " test "; });
foreach (var item in newList)
{
Console.WriteLine(item);
}
Solution 3 - C#
Based on Steve's answer, the simplest expression would be this:
var combo = from Person in people
from Car in cars
select new {Person, Car};
Solution 4 - C#
A Tuple
is a good type for Cartesian product:
public static IEnumerable<Tuple<T1, T2>> CrossJoin<T1, T2>(IEnumerable<T1> sequence1, IEnumerable<T2> sequence2)
{
return sequence1.SelectMany(t1 => sequence2.Select(t2 => Tuple.Create(t1, t2)));
}
Solution 5 - C#
Extension Method:
public static IEnumerable<Tuple<T1, T2>> CrossJoin<T1, T2>(this IEnumerable<T1> sequence1, IEnumerable<T2> sequence2)
{
return sequence1.SelectMany(t1 => sequence2.Select(t2 => Tuple.Create(t1, t2)));
}
And use like:
vals1.CrossJoin(vals2)