src/WorkerF/DB/Drivers/PDODriver.php
public function count($field = '*')
    {
        if (trim($field) != '*') {
            $field = self::_quote($field);
        }
        $this->_cols_str = ' COUNT('.$field.') AS count_num ';

        return $this->row()['count_num'];
    }
public function count($field = '*')
    {
        if (trim($field) != '*') {
            $field = self::_quote($field);
        }
        $this->_cols_str = ' COUNT('.$field.') AS count_num ';

        return $this->row()['count_num'];
    }
get count

@param  string $field
@return  int
@throws  \PDOException