The query takes a long time - mysql

Question

am I doing this SQL code right? The query works, but it takes really long, 161 seconds (with LIMIT 2 set). Is there a way to optimize that?
SELECT p.itemid as `id`,
p.title as `name`,
pb.data_txt as `birthdate`,
pc.data_txt as `growth`,
pd.data_txt as `eyes`,
pe.data_txt as `desc`,
pf.data_txt as `weight`,
pg.data_txt as `sex`,
ph.data_txt as `hair`,
pi.data_txt as `dimensions`,
pj.data_txt as `lang`,
pk.data_txt as `school`,
pl.data_txt as `know`,
p.image as `image`
FROM `jos_sobi2_item` p
INNER JOIN `jos_sobi2_fields_data` AS pb ON pb.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pc ON pc.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pd ON pd.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pe ON pe.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pf ON pf.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pg ON pg.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS ph ON ph.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pi ON pi.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pj ON pj.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pk ON pk.itemid = p.itemid
INNER JOIN `jos_sobi2_fields_data` AS pl ON pl.itemid = p.itemid
WHERE
pb.fieldid = 16 AND
pc.fieldid = 17 AND
pd.fieldid = 21 AND
pe.fieldid = 13 AND
pf.fieldid = 18 AND
pg.fieldid = 19 AND
ph.fieldid = 20 AND
pi.fieldid = 22 AND
pj.fieldid = 25 AND
pk.fieldid = 23 AND
pl.fieldid = 24
LIMIT 2
I think part of the INNER JOIN is bad.

Answer 1

Try using conditional aggregation instead:
SELECT p.itemid as `id`, p.title as `name`,
max(case when fd.fieldid = 16 then data_txt end) as birthdate,
max(case when fd.fieldid = 17 then data_txt end) as growth,
. . .
FROM `jos_sobi2_item` p INNER JOIN
`jos_sobi2_fields_data` fd
ON fd.itemid = p.itemid
GROUP BY p.itemId, p.title;
You can add as many fields as you like, and adding more fields will have little impact on performance.
If you really want this even faster, you can do the limit on the first table:
SELECT p.itemid as `id`, p.title as `name`,
max(case when fd.fieldid = 16 then data_txt end) as birthdate,
max(case when fd.fieldid = 17 then data_txt end) as growth,
. . .
FROM (select p.*
from `jos_sobi2_item` p
limit 2
) p INNER JOIN
`jos_sobi2_fields_data` fd
ON fd.itemid = p.itemid
GROUP BY p.itemId, p.title;