public static void AddJoin(DQueryDom mainDom, JoinAlias selfAlias)
{
var root = mainDom.From.RootSource.Alias;
var datediff =
DQExpression.DateDiff(DQExpression.Field(selfAlias, "Date"), DQExpression.Field(root, "Time"));
mainDom.From.AddJoin(JoinType.Left, new DQDmoSource(selfAlias), DQCondition.And(
DQCondition.EQ(DQExpression.Value(-1), datediff),
DQCondition.EQ(selfAlias, "Goods_ID", root, "Goods_ID")));
}