以下哪項更快,還是相當? (從抓timestamp列最近期的記錄)帶時間戳條件的性能
SELECT UNIX_TIMESTAMP(`modified`) stamp
FROM `some_table`
HAVING stamp > 127068799
ORDER BY stamp DESC
或
SELECT UNIX_TIMESTAMP(`modified`) stamp
FROM `some_table`
WHERE UNIX_TIMESTAMP(`modified`) > 127068799
ORDER BY `modified` DESC
甚至另一個組合?
HAVING旨在與GROUP BY子句一起使用 – jab 2010-04-08 11:25:15