我只是wounder是否會有大的性能差異白衣這2個查詢SQL查詢性能LIKE和wildecards主場迎戰
SELECT
`items_id`, `sport_id`, `sport`, `title`, `url`,
`Select3`, `Select6`, `id`, `data`,`image` as image,
concat('index.php?option=sports&item=',`items_id`,'&p=C108-M108') as count_url
FROM
qy9zh_dataitems
WHERE Select6 LIKE '%sport%'
ORDER BY `Select9` DESC LIMIT 0, 4
SELECT
`items_id`, `sport_id`, `sport`, `title`, `url`,
`Select3`, `Select6`, `id`, `data`,`image` as image,
concat('index.php?option=sports&item=',`items_id`,'&p=C108-M108') as count_url
FROM
qy9zh_dataitems
WHERE Select6 in ('sport')
ORDER BY `Select9` DESC LIMIT 0, 4
的查詢工作就好了..他們兩個..只是擔心性能:)
編輯:一件奇怪的事,當我做了一些測試是這樣的:
SELECT * FROM qy9zh_dataitems WHERE Select6 in ('kvinna') LIMIT 0, 40000
29051總計,查詢花費0.2581秒
SELECT * FROM qy9zh_dataitems WHERE Select6 LIKE ('%kvinna%') LIMIT 0, 40000
29113總計,查詢花費0.2218秒
你知道這兩個查詢有不同的結果嗎? – danihp 2012-01-30 21:34:14
結果不是問題..只是對性能好奇:) – Mackelito 2012-01-30 21:36:43
殺性能問題是第一個查詢中的起始通配符。 – danihp 2012-01-30 21:39:04