Question

I have a MembershipGroups table that is associated with a child Members table. The Members table has a Status column which can be set to Active or Inactive.

I want to select all MembershipGroups and only their active Members

As an example,

MembershipGroups

ID—-Title

1—–Group #1

2—–Group #2

Members

MembershipGroupID-Name–Status

1————————-John—-Active

1————————-Sally—-Inactive

1————————-David—Inactive

I’m trying to create a query that looks something like the following (which doesn’t currently work):

var query = from mg in db.MembershipGroups
where mg.Members.Status = "Active"
select mg

The result for this example should return a MembershipGroup of ID#1 with only one child Member entity

How can use LINQ-to-SQL to select a parent object that filters on child objects? If I were using straight T-SQL then this would be a simple join with a where clause but it seems to be much more difficult to do using LINQ-to-SQL.

Answer 1

Edit – Updated answer to return the MemberShipGroup object

var query = (from mg in db.MembershipGroups
            join m in db.Members.Where(mem => mem.Status == "Active")
            on mg.ID equals m.MembershipGroups into members
            select new
            {
               MembershipGroup = mg,
               Members = members
            }).AsEnumerable()
              .Select(m => new MembershipGroup  
                           {
                             ID = m.MembershipGroup.ID,
                             Title = m.MembershipGroup.Title,
                             Members = m.Members 
                           });