title: Entity Framework GroupJoin different result vs join with group
body: <p>I try to convert this query syntax:</p>
  
  <pre><code> res = from co in db.SALES
                    join
                     op in db.OPERATORS
                     on co.ID_OP equals op.ID
                    where co.DATA_CLOSE == null
                    group new { co, op } by new { op.ID, op.NAME } into g
                    select new
                    {
                        ID = g.Key.ID,
                        NAME= g.Key.NAME,
                        COUNT = g.Select(x =&gt; x.co).Count()
  
                    };
  </code></pre>
  
  <p>to method syntax:</p>
  
  <pre><code>res= db.OPERATORS.GroupJoin(
                db.SALES.Where(c=&gt;c.DATA_CLOSE==null),
                 op =&gt; op.ID,
                 co =&gt; co.ID_OP,
               (co, grp) =&gt;
               new 
          {
              NAME= co.NAME,
              COUNT    = grp.Select(x=&gt;x.ID ).Count()
               });
  </code></pre>
  
  <p>first query works as expected,just like inner join,I got only operators with opened sales count
  second give me ALL operators with opened sales count,if there is no opened sale,it give me 0,
  how to make second query to work like the first one </p>
  
  <p>thanks</p>