Hiya
Description:
I have a query which uses a index (acording to explain)
when i do the same query with a orderby added mysql doesn't use the index
(the field that is used to do order by is indexed)
Release MySQL 3.22.32 and 3.22.26a (both from source)
How-To-Repeat:
dump the attached file into a db
and try these query's:
the "good" query: (explain says using index)
SELECT SQL_SMALL_RESULT HIGH_PRIORITY STRAIGHT_JOIN COUNT(search.page_id)
AS counter, search.page_id FROM word, search WHERE (word.word LIKE 'zorg%')
AND search.word_id = word.id GROUP BY search.page_id ORDER BY counter DESC
the "bad" query: (no index here :( )
SELECT SQL_SMALL_RESULT HIGH_PRIORITY STRAIGHT_JOIN COUNT(search.page_id)
AS counter, search.page_id FROM word, search WHERE (word.word LIKE 'zorg%')
AND search.word_id = word.id GROUP BY search.page_id ORDER BY counter DESC,
search.count DESC
Greetz,
Wico
| Thread |
|---|
| • Mysql Loosses indexes when adding ORDER BY to a query | Wico de Leeuw | 7 Mar |