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Re: Optimize subquery, replace IN() with JOIN
Posted by: Miron jajtic
Date: November 15, 2016 04:25PM

Thank you, Peter.
Unfortunately does not work as expected
It returns several rows with the same content.

Here are table structure and sample datas: http://textuploader.com/d5zhr

Test run with your query:

mysql> SELECT a.id, a.title, a.alias
FROM content AS a
JOIN category_content_se AS b ON a.id = b.content_id
WHERE a.id =1842
AND b.content_typ = 'actual'
ORDER BY a.date_add DESC
LIMIT 10;
+------+------------------------+------------------------+
| id | title | alias |
+------+------------------------+------------------------+
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
+------+------------------------+------------------------+
7 rows in set (0.00 sec)


Test run with original query:

mysql> SELECT id, title, alias
FROM content
WHERE published = '1'
AND typ = 'actual'
AND id
IN (
SELECT content_id
FROM category_content_se
WHERE category_id
IN (
SELECT category_id
FROM category_content_se
WHERE content_id = '1842'
)
AND content_typ = 'actual'
)
ORDER BY date_add DESC
LIMIT 10;
+------+--------------------------------------------------+--------------------------------------------------+
| id | title | alias |
+------+--------------------------------------------------+--------------------------------------------------+
| 1876 | Prljava kampanja | Prljava kampanja |
| 1848 | Stablo nerada u Vrhovinama | Stablo nerada u Vrhovinama |
| 1847 | Zbogom Åzivotu pod maskama | Zbogom zivotu pod maskama |
| 1842 | Gdje je nestala pravda | Gdje je nestala pravda |
| 1838 | Pastrva je stara, uprava je nova | Pastrva je stara uprava je nova |
| 1837 | Pozeljna udavaca | Pozeljna udavaca |
| 1835 | Posmrtna knjiga kontraverznog srpskog politicara | Posmrtna knjiga kontraverznog srpskog politicara |
| 1831 | don Angelo iz duse | don Angelo iz duse |
| 1828 | Sajam poslova u Otoccu | Sajam poslova u Otoccu |
| 1824 | Pravda spora, ali dostizna | Pravda spora ali dostizna |
+------+--------------------------------------------------+--------------------------------------------------+
10 rows in set (0.00 sec)

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Re: Optimize subquery, replace IN() with JOIN
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November 15, 2016 04:25PM


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