LINQ Join 多條件

var dnrs = context.participants.GroupJoin( context.prereg_participants, x => new { JoinCol1 = x.barcode, JoinCol2 = x.event_id }, // Left table join key y => new { JoinCol1 = y.barcode, JoinCol2 = y.event_id }, // Right table join key ...

from a in db.Students join b in db.Schools on new { SchoolId = a.SchoolId, IsMale = a.IsMale } equals new { SchoolId = b.Id, IsMale = true }