/**
*
* having('SUM(a)=?', 1) => "HAVING SUM(a)=1"
* having('a>?', Sql::native('now()')) => "HAVING a>now()"
* having('a IN (?)', [1, 2]) => "HAVING a IN (1,2)"
*
* @param string $expr
* @param string $_
* @return \phprs\ezsql\rules\select\OrderByRule
*/
public function having($expr, $_ = null)
{
WhereImpl::having($this->context, $expr, array_slice(func_get_args(), 1));
return new OrderByRule($this->context);
}