i don't know how to create the index about the following statement.
SELECT b.screen_id AS screen_id, b.name AS screen_name
FROM tbl_showlog AS a CROSS JOIN
tbl_screen AS b CROSS JOIN
tbl_company AS c
WHERE a.screen_id = b.screen_id
AND b.company_id = c.company_id
AND c.company_id = 1
AND c.is_active = 1
GROUP BY b.screen_id, b.name
ORDER BY b.screen_id
many thx!