Last 10 record and Sort (Sub-Query)

/*
 * 1. select last 10 record and sort.
 * 2. calc (`rowsA` + `rowsB`) / `rowsC`.
 * 3. use Sub-Query.
 */

SELECT `record_time`, `tmp` FROM (

    SELECT
    `record_time`,
    round(((`rowsA` + `rowsB`) / (SELECT rowsC FROM tableB WHERE bid = '1') * 100), 2) AS 'tmp'
    FROM tableA ORDER BY `record_time` DESC LIMIT 10

) AS `lab_last_10_sort` ORDER BY `record_time` ASC;