私は約を保持する次の表を持っています。700K レコード:
CREATE TABLE `trades` (
`tradeId` int(11) NOT NULL AUTO_INCREMENT,
`userId` int(11) NOT NULL,
`visible` int(11) NOT NULL DEFAULT '1',
`sourceItem` int(11) NOT NULL,
`sourceKeyTierId` int(11) DEFAULT NULL,
`sourceKeyTypeId` int(11) DEFAULT NULL,
`sourceKeyAmount` int(11) DEFAULT NULL,
`sourceModId` int(11) DEFAULT NULL,
`sourceModLevel` int(11) DEFAULT NULL,
`destinationItem` int(11) NOT NULL,
`destinationPlatinum` int(11) DEFAULT NULL,
`destinationKeyTierId` int(11) DEFAULT NULL,
`destinationKeyTypeId` int(11) DEFAULT NULL,
`destinationKeyAmount` int(11) DEFAULT NULL,
`destinationModId` int(11) DEFAULT NULL,
`destinationModLevel` int(11) DEFAULT NULL,
`added` datetime NOT NULL,
PRIMARY KEY (`tradeId`),
KEY `userId` (`userId`),
KEY `sourceKeyTierId` (`sourceKeyTierId`),
KEY `sourceKeyTypeId` (`sourceKeyTypeId`),
KEY `sourceModId` (`sourceModId`),
KEY `destinationKeyTierId` (`destinationKeyTierId`),
KEY `destinationKeyTypeId` (`destinationKeyTypeId`),
KEY `destinationModId` (`destinationModId`),
CONSTRAINT `trades_ibfk_1` FOREIGN KEY (`userId`) REFERENCES `users` (`userId`),
CONSTRAINT `trades_ibfk_2` FOREIGN KEY (`sourceKeyTierId`) REFERENCES `keytiers` (`keyTierId`),
CONSTRAINT `trades_ibfk_3` FOREIGN KEY (`sourceKeyTypeId`) REFERENCES `keytypes` (`keyTypeId`),
CONSTRAINT `trades_ibfk_4` FOREIGN KEY (`sourceModId`) REFERENCES `mods` (`modId`),
CONSTRAINT `trades_ibfk_5` FOREIGN KEY (`destinationKeyTierId`) REFERENCES `keytiers` (`keyTierId`),
CONSTRAINT `trades_ibfk_6` FOREIGN KEY (`destinationKeyTypeId`) REFERENCES `keytypes` (`keyTypeId`),
CONSTRAINT `trades_ibfk_7` FOREIGN KEY (`destinationModId`) REFERENCES `mods` (`modId`)
) ENGINE=InnoDB AUTO_INCREMENT=732566 DEFAULT CHARSET=latin1
次のクエリで見られるように、クエリを実行して 10 個の結果を取得します。
(SELECT 'Key' AS tradeOrigin,
CONCAT(skti.tier, ' ', skty.type) AS trade,
CONCAT('Amount: ', t.sourceKeyAmount) AS tradeInfo,
'Platinum' AS tradeToOrigin,
t.destinationPlatinum AS tradeTo,
'' AS tradeToInfo,
u.ingame AS seller,
DAYSPASSED(added) AS daysPassed,
DATEDIFF(NOW(), added) AS sortingSince
FROM trades t
JOIN users u ON t.sourceItem = 1
AND t.destinationItem = 1
AND t.visible = 1
AND t.userId = u.userId
JOIN keytiers skti ON t.sourceKeyTierId = skti.keyTierId
JOIN keytypes skty ON t.sourceKeyTypeId = skty.keyTypeId)
UNION ALL
(SELECT 'Key' AS tradeOrigin,
CONCAT(skti.tier, ' ', skty.type) AS trade,
CONCAT('Amount: ', t.sourceKeyAmount) AS tradeInfo,
'Key' AS tradeToOrigin,
CONCAT(dkti.tier, ' ', dkty.type) AS tradeTo,
CONCAT('Amount: ', t.destinationKeyAmount) AS tradeToInfo,
u.ingame AS seller,
DAYSPASSED(added) AS daysPassed,
DATEDIFF(NOW(), added) AS sortingSince
FROM trades t
JOIN users u ON t.sourceItem = 1
AND t.destinationItem = 2
AND t.visible = 1
AND t.userId = u.userId
JOIN keytiers skti ON t.sourceKeyTierId = skti.keyTierId
JOIN keytypes skty ON t.sourceKeyTypeId = skty.keyTypeId
JOIN keytiers dkti ON t.destinationKeyTierId = dkti.keyTierId
JOIN keytypes dkty ON t.destinationKeyTypeId = dkty.keyTypeId)
UNION ALL
(SELECT 'Key' AS tradeOrigin,
CONCAT(skti.tier, ' ', skty.type) AS trade,
CONCAT('Amount: ', t.sourceKeyAmount) AS tradeInfo,
'Mod' AS tradeToOrigin,
dm.name AS tradeTo,
CONCAT('Level: ', IF(t.destinationModLevel = 0, 'Unranked', t.destinationModLevel)) AS tradeToInfo,
u.ingame AS seller,
DAYSPASSED(added) AS daysPassed,
DATEDIFF(NOW(), added) AS sortingSince
FROM trades t
JOIN users u ON t.sourceItem = 1
AND t.destinationItem = 3
AND t.visible = 1
AND t.userId = u.userId
JOIN keytiers skti ON t.sourceKeyTierId = skti.keyTierId
JOIN keytypes skty ON t.sourceKeyTypeId = skty.keyTypeId
JOIN mods dm ON t.destinationModId = dm.modId)
UNION ALL
(SELECT 'Mod' AS tradeOrigin,
sm.name AS trade,
CONCAT('Level: ', IF(t.sourceModLevel = 0, 'Unranked', t.sourceModLevel)) AS tradeInfo,
'Platinum' AS tradeToOrigin,
t.destinationPlatinum AS tradeTo,
'' AS tradeToInfo,
u.ingame AS seller,
DAYSPASSED(added) AS daysPassed,
DATEDIFF(NOW(), added) AS sortingSince
FROM trades t
JOIN users u ON t.sourceItem = 2
AND t.destinationItem = 1
AND t.visible = 1
AND t.userId = u.userId
JOIN mods sm ON t.sourceModId = sm.modId)
UNION ALL
(SELECT 'Mod' AS tradeOrigin,
sm.name AS trade,
CONCAT('Level: ', IF(t.sourceModLevel = 0, 'Unranked', t.sourceModLevel)) AS tradeInfo,
'Key' AS tradeToOrigin,
CONCAT(dkti.tier, ' ', dkty.type) AS tradeTo,
CONCAT('Amount: ', t.destinationKeyAmount) AS tradeToInfo,
u.ingame AS seller,
DAYSPASSED(added) AS daysPassed,
DATEDIFF(NOW(), added) AS sortingSince
FROM trades t
JOIN users u ON t.sourceItem = 2
AND t.destinationItem = 2
AND t.visible = 1
AND t.userId = u.userId
JOIN mods sm ON t.sourceModId = sm.modId
JOIN keytiers dkti ON t.destinationKeyTierId = dkti.keyTierId
JOIN keytypes dkty ON t.destinationKeyTypeId = dkty.keyTypeId)
UNION ALL
(SELECT 'Mod' AS tradeOrigin,
sm.name AS trade,
CONCAT('Level: ', IF(t.sourceModLevel = 0, 'Unranked', t.sourceModLevel)) AS tradeInfo,
'Mod' AS tradeToOrigin,
dm.name AS tradeTo,
CONCAT('Level: ', IF(t.destinationModLevel = 0, 'Unranked', t.destinationModLevel)) AS tradeToInfo,
u.ingame AS seller,
DAYSPASSED(added) AS daysPassed,
DATEDIFF(NOW(), added) AS sortingSince
FROM trades t
JOIN users u ON t.sourceItem = 2
AND t.destinationItem = 3
AND t.visible = 1
AND t.userId = u.userId
JOIN mods sm ON t.sourceModId = sm.modId
JOIN mods dm ON t.destinationModId = dm.modId) LIMIT 0,
10
このクエリには 196 秒かかるため、いくつかのサブクエリに制約 ( ORDER BY、 )を設定する必要があることは明らかです。LIMIT
私はそれらを追加する方法について混乱していますLIMITが、次のPHPで動的に選択します:
//Limiting
$offset = ($page - 1) * $limit;
$sql .= " LIMIT {$offset}, {$limit}";
ページシステムを使用して結果を表示しているので、次の目的で機能するものが必要です。
- ~700K 行からの結果 0 から 9
- ~700K 行からの結果 10 から 19
- 等
- ~700K 行からの結果 699990 から 699999
結果セットの末尾のみが必要な場合は、20 レコードが必要だとします。次に、レコードを失わないようにするために、すべてのサブクエリ20 * [subquery_count]でレコードを取得する必要があります。
しかし、オフセットも考慮する必要があるので、どうすればよいでしょうか?