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我有這個查詢顯示在MySql慢查詢日誌中。 (這並不慢,但它沒有使用索引權)。我需要一些關於如何設置索引的幫助。如何爲此MySql查詢設置正確的索引?
SELECT tbladded.amount*SUM(tbladdeditem.amount)
FROM tbladded
INNER JOIN tbladdeditem ON tbladded.addedid = tbladdeditem.addedid AND tbladdeditem.deleted='False'
WHERE tbladded.userid=100
AND tbladded.date='2012-01-01'
AND tbladded.deleted='False'
GROUP BY tbladded.addedid
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE tbladded ref PRIMARY,userid_date userid_date 8 const,const 1 Using where
1 SIMPLE tbladdeditem ref addedid addedid 5 tbladded.addedid 1 Using where
這是表什麼樣子:
CREATE TABLE `tbladded` (
`addedid` int(11) NOT NULL AUTO_INCREMENT,
`amount` double DEFAULT NULL,
`date` date DEFAULT NULL,
`userid` mediumint(9) DEFAULT NULL,
`deleted` enum('False','True') CHARACTER SET latin1 DEFAULT 'False',
PRIMARY KEY (`addedid`),
KEY `userid_date` (`userid`,`date`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `tbladdeditem` (
`addeditemid` int(11) NOT NULL AUTO_INCREMENT,
`amount` double DEFAULT NULL,
`addedid` int(11) DEFAULT NULL,
`userid` mediumint(9) DEFAULT NULL,
`deleted` enum('False','True') CHARACTER SET latin1 DEFAULT 'False',
PRIMARY KEY (`addeditemid`),
KEY `addedid` (`addedid`),
KEY `userid` (`userid`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
是你的 'GROUP BY tbladded.addedid' neccessary? – user1027167 2012-02-29 12:40:42
@ user1027167對不起,GROUP BY是需要的,我錯過了查詢中的SUM()。 – Martin 2012-03-01 09:19:27