Помогите оптимизировать запрос SQL

SELECT ROUND(professions.average, 1)
AS rate, master.category_id, master.shortname, 0
AS count, t2.morpher
AS name, CONCAT_WS('-', master.id, master.alias)
AS item_alias, CONCAT_WS('-', t2.id, t2.alias)
AS category_alias
FROM x_spec_items AS master
INNER JOIN x_spec_categories AS t2 ON master.category_id = t2.id
INNER JOIN x_spec_sections AS t3 ON master.section_id = t3.id
LEFT JOIN x_spec_professions AS professions ON master.id = professions.item_id
WHERE master.section_id = '160'
GROUP BY master.id
ORDER BY master.average ASC, t2.name ASC