[Solved]-Entity Framework 6.1.1 DbJoinExpression get all left columns-LINQ,C#

to select all properties of property l just select it whole:

return expression.innerjoin(
    dbexpressionbuilder.scan(joinentity),
        (l, r) => dbexpressionbuilder.equal(
                    dbexpressionbuilder.property(l, "joinid"),
                    dbexpressionbuilder.property(r, "joinid")
                )
    )
    .select(exp => exp.property("l"));

this will automatically generate query selecting all columns that "l" has.