mysql: fast group by with join - mysql

Question

I have this query with many left joins and a inner join with dates.
I need to group by id_art (from articles_art) and date_dat (dates_dat). The problem is that is really slow. it takes 3second for 1000records.
dates_dat is indexed in dates_dat table and id_art is a primary key of articles_art.
What can I do to optimize this query?
SELECT
id_art, image2_art, video_art, website,
text.title_int, text.intro_int, text.text_int, text.extra_int,
dat.date_dat, dat.date2_dat,
group_concat(tim.time_tim),
prd.name_prd,
group_concat(cat.name_cat),
trg.name_trg,
spa.name_spa,
spa2.name_spa
FROM
articles_art AS art
LEFT JOIN internText_int AS text ON text.idart_int = art.id_art
INNER JOIN dates_dat AS dat ON art.id_art = dat.idart_dat
LEFT JOIN spaces_spa As spa ON spa.id_spa = dat.idspa_dat
LEFT JOIN spaces_spa As spa2 ON spa.id_spa = dat.idspa2_dat
LEFT JOIN times_tim AS tim ON tim.iddat_tim = dat.id_dat
LEFT JOIN articles_products_artprd AS artprd ON artprd.idart_artprd = art.id_art
LEFT JOIN products_prd AS prd ON prd.id_prd = artprd.idprd_artprd
LEFT JOIN cater_cev AS cev ON cev.idart_cev = dat.idart_dat
LEFT JOIN categories_cat AS cat ON cat.id_cat = cev.idcat_cev
LEFT JOIN targets_trg AS trg ON trg.id_trg = art.idtrg_art
WHERE
prd.id_prd in (1,2)
AND validated_art = 1
AND text.idlin_int in (1,4)
GROUP BY
id_art, date_dat

Answer 1

Look like you can put an index on these columns
prd.id_prd
validated_art
text.idlin_int
Test this first then if this does not work put indexes on column conditions on the ON clause

Answer 2

If data latency isn't an issue, can you hive the data off (perhaps overnight?) into a single normalised table? That way you query a single table without all those JOINS. You could even apply indexes to help speed things up further.