Help me to optimize this query - mysql

Question

Please suggest indexes to optimize below query. I couldn't allowed to rewrite the query but create indexes:
SELECT
`ADV`.`inds` as `c0`,
sum(`ADVpost`.`clk`) as `m0`
FROM
(SELECT *
FROM advts
WHERE comp_id =
(SELECT comp_id
FROM comp
WHERE name = 'abc')) as `ADV`,
(SELECT dt_id,
comp_id,
b_id,
ad_id,
clk,
resp
FROM advts_post
WHERE comp_id =
(SELECT comp_id
FROM comp
WHERE name = 'abc')) as `ADVpost`
WHERE
`ADVpost`.`ad_id` = `ADV`.`ad_id`
GROUP BY
`ADV`.`inds`
ORDER BY
ISNULL(`ADV`.`inds`), `ADV`.`inds` ASC
The explain for the query is as:
select_type table type possible_keys Extra
PRIMARY <derived2> ALL null Using temporary; Using filesort
PRIMARY <derived4> ALL null Using where; Using join buffer
DERIVED ADVpost ALL null Using where
SUBQUERY comp ALL null Using where
DERIVED advts ALL null Using where
SUBQUERY comp ALL null Using where
Existing indexes are as follows:
ADVpost > PRIMARY KEY (`dt_id`,`comp_id`,`b_id`,`ad_id`)
comp > PRIMARY KEY (`comp_id`)
advts > PRIMARY KEY (`ad_id`)
Thanks in advance.

Answer 1

Ok, maybe I am not an expert with MySQL optimization, but:
if it is possible and reasonable, try to avoid subselects where possible (instead it may be better to make separate query and then pass the retrieved ID, like comp_id, to the containing query),
put index on comp.name,
put index on advts_post.comp_id (single one),
put index on advts_post.ad_id (single one),
Maybe it is rather simple, but should help at least slightly make it faster. Tell us about the results.

Answer 2

That query is a dogs dinner - whoever wrote it should be severely punished, and the person who said you can't rewrite it but must make it run faster should be shot.
Loose the sub-selects!
MySQL does not do push-predicates very well (at all?).
Use proper joins instead and state implied joins:
SELECT ap.inds, SUM(ap.clk)
FROM advts_post AS ap
, comp AS co
, advts ad
WHERE ap.comp_id = co.comp_id
AND ad.comp_id = co.comp_id
AND ap.comp_id = ad.comp_id
AND co.name='abc'
GROUP BY ap.inds
ORDER BY ISNULL(ap.inds), ap.inds ASC