我知道這裏有一千個類似的問題,但沒有一個像我一樣處理複雜的查詢(並且我的MySQL技巧並不重要。真正瞭解如何適應它們)優化MySQL查詢以避免「使用臨時」和「使用filesort」
這就是:
explain select
`ev`.`EventID` AS `EventID`
,`ev`.`EventName` AS `EventName`
,concat(`ev`.`EventDate`,' ',`ev`.`StartTime`) AS `EventDT`
,`ev`.`NumberTicketsAvailable` AS `TotalTickets`
,`ev`.`Soldout` AS `Soldout`
,count((case when (`ec`.`CartStatus` = 'InCart') then 1 else NULL end)) AS `InCartCount`
,count((case when (`ec`.`CartStatus` = 'InPayment') then 1 else NULL end)) AS `InPaymentCount`
,count((case when (`ec`.`CartStatus` = 'Paid') then 1 else NULL end)) AS `PaidCount`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 604800 second) > now())) then 1 else NULL end)) AS `PaidOverWeek`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 432000 second) > now())) then 1 else NULL end)) AS `PaidOverFiveDays`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 86400 second) > now())) then 1 else NULL end)) AS `PaidOverDay`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 43200 second) > now())) then 1 else NULL end)) AS `PaidOverHalfDay`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 21600 second) > now())) then 1 else NULL end)) AS `PaidOverQuarterDay`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 10800 second) > now())) then 1 else NULL end)) AS `PaidOverThreeHours`
,count((case when ((`ec`.`CartStatus` = 'Paid') and ((`ec`.`DateRecordModified` + interval 3600 second) > now())) then 1 else NULL end)) AS `PaidOverHour`
from (`Events` `ev`
left join (`Events_EventCart_Rel` `eecr`
left join `EventCart` `ec`
on((`eecr`.`EventCartID` = `ec`.`EventCartID`)))
on((`ev`.`EventID` = `eecr`.`EventID`)))
where (`eecr`.`Active` = 1 AND `eecr`.`Deleted` = 'No')
group by
`ev`.`EventID`
,`ev`.`EventName`
,`ev`.`EventDate`
,`ev`.`StartTime`
,`ev`.`NumberTicketsAvailable`
,`ev`.`Soldout`;
這樣做的結果是這樣的:
+-id-+-select_type-+-table-+--type--+--------possible_keys--------+----key----+-key_len-+----------ref----------+--rows--+---------------------------Extra---------------------------+
| 1| SIMPLE | eecr | index | EventID,EventID_2,EventID_3 | EventID_3 | 10 | {null} | 17609 | Using where; Using index; Using temporary; Using filesort |
| 1| SIMPLE | ev | eq_ref | PRIMARY | PRIMARY | 4 | eecr.EventID | 1 | Using where |
| 1| SIMPLE | ec | eq_ref | PRIMARY | PRIMARY | 4 | eecr.EventCartID | 1 | |
+----+-------------+-------+--------+-----------------------------+-----------+---------+-----------------------+--------+-----------------------------------------------------------+
而表定義:
CREATE TABLE IF NOT EXISTS `Events` (
`EventID` int(10) unsigned NOT NULL AUTO_INCREMENT,
`EventName` varchar(150) NOT NULL,
`StartTime` char(8) NOT NULL DEFAULT '00:00:00',
`EndTime` char(8) NOT NULL DEFAULT '00:00:00',
`EventDate` varchar(20) NOT NULL,
`NumberTicketsAvailable` smallint(6) DEFAULT NULL,
`Soldout` enum('yes','no') DEFAULT 'no',
#...
PRIMARY KEY (`EventID`),
KEY `EndTime` (`EndTime`,`EventDate`),
KEY `StartTime` (`StartTime`,`EventDate`),
KEY `EventDate` (`EventDate`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
CREATE TABLE IF NOT EXISTS `Events_EventCart_Rel` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`EventCartID` int(11) NOT NULL,
`EventID` int(11) NOT NULL,
`DateAdded` datetime NOT NULL,
`PersonID` int(11) NOT NULL,
`SeatTypeID` int(11) NOT NULL,
`MealChoiceID` int(11) NOT NULL,
`Active` tinyint(1) NOT NULL DEFAULT '1',
`Deleted` enum('Yes','No') NOT NULL DEFAULT 'No',
`ModifiedByAdmin` enum('Yes','No') NOT NULL DEFAULT 'No',
PRIMARY KEY (`ID`),
KEY `EventID` (`EventID`,`PersonID`),
KEY `EventCartID` (`EventCartID`),
KEY `EventID_2` (`EventID`),
KEY `EventID_3` (`EventID`,`EventCartID`,`Active`,`Deleted`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
CREATE TABLE IF NOT EXISTS `EventCart` (
`EventCartID` int(11) NOT NULL AUTO_INCREMENT,
`RegistrantsID` int(11) NOT NULL DEFAULT '0',
`DateRecordCreated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`DateRecordModified` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`CartStatus` enum('InCart','InPayment','Paid') NOT NULL DEFAULT 'InCart',
`ModifiedByAdmin` enum('yes','no') NOT NULL DEFAULT 'no',
PRIMARY KEY (`EventCartID`),
KEY `rid` (`RegistrantsID`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
爲了搶佔任何疑惑看待這些列 - 是的,有很多遺留類型的東西,我沒有時間修復代碼。
解釋計劃對我來說聽起來很合理。有什麼困難? – 2010-09-07 15:55:41
這需要約2.5秒。無論如何都不可怕,但我喜歡貪婪。這是針對「實時」報告的,我希望儘可能減少執行時間。 – 2010-09-07 16:03:21