If you prefer method call notation, you can force a left join using SelectMany
combined with DefaultIfEmpty
. At least on Entity Framework 6 hitting SQL Server. For example:
using(var ctx = new MyDatabaseContext())
{
var data = ctx
.MyTable1
.SelectMany(a => ctx.MyTable2
.Where(b => b.Id2 == a.Id1)
.DefaultIfEmpty()
.Select(b => new
{
a.Id1,
a.Col1,
Col2 = b == null ? (int?) null : b.Col2,
}));
}
(Note that MyTable2.Col2
is a column of type int
).
The generated SQL will look like this:
SELECT
[Extent1].[Id1] AS [Id1],
[Extent1].[Col1] AS [Col1],
CASE WHEN ([Extent2].[Col2] IS NULL) THEN CAST(NULL AS int) ELSE CAST( [Extent2].[Col2] AS int) END AS [Col2]
FROM [dbo].[MyTable1] AS [Extent1]
LEFT OUTER JOIN [dbo].[MyTable2] AS [Extent2] ON [Extent2].[Id2] = [Extent1].[Id1]