/**
* @param $table
* @param $key $table.key
* @param bool $fkey $this->table.key
* @return $this
*/
public function leftJoinOn($table, $key, $fkey = false)
{
$fkey = $fkey ?: $key;
$key = starts_with($key, $table . '.') ? $key : $table . '.' . $key;
$fkey = starts_with($key, $this->table . '.') ? $fkey : $this->table . '.' . $fkey;
$this->operator = $this->operator->leftJoin($table, $key, '=', $fkey);
return $this;
}