标签：var star pad number stat interface compact unique general
先创建一个数据库test， 再建立一个表格devices，(这里建立多个字段来演示效果)
CREATE TABLE `devices` ( `id` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT ‘‘, `TVName` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `TVModelNumber` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `TVSerialNumber` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `TVRoomID` int(11) DEFAULT NULL, `TVMACAddress` varchar(17) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `TVIPAddress` varchar(15) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `VSecureTVID` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `Type` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `PowerStatus` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `TVUniqueID` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `FirmwareId` int(11) DEFAULT NULL, `CloneId` int(11) DEFAULT NULL, `LastCloneRename` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT ‘{\"old\":\"Unknown\",\"new\":\"Unknown\"}‘, `Status` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `Progress` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `TVStatus` text CHARACTER SET utf8 COLLATE utf8_general_ci, `si_clone_Identifiers` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `si_firmware_Identifier` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `tv_clone_Identifiers` varchar(8000) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `tv_firmware_Identifier` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `success_siclone_Identifier` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `success_tvclone_Identifier` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `clone_color` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT ‘black‘, `fw_color` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT ‘black‘, `CreatedDate` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `ModifiedDate` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `Lastonline` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `clone_mode` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT ‘Upgrade‘, `upload_progress` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT ‘ST‘, `upload_session_id` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `upload_session_start` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `upload_session_end` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `upload_session_status` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `channel_color` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `app_color` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `upgrade_type` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `si_Identifiers` text CHARACTER SET utf8 COLLATE utf8_general_ci, `networkInterfaceIp` varchar(15) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL, `clone_type` varchar(45) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT ‘None‘, PRIMARY KEY (`id`) USING BTREE, INDEX `FirmwareId`(`FirmwareId`) USING BTREE, INDEX `CloneId`(`CloneId`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
我这里想这个表devices里面添加了8000条数据.
SELECT * FROM `devices` limit 7000,10 #0.015s这里消耗的时间是0.015s
select * from `devices` where id > (select id from devices limit 7000,1) limit 10 #0.002s这里消耗的时间是0.002s
同样的分页查询, 消耗时间不一样
待续…
标签：var star pad number stat interface compact unique general
原文地址：https://www.cnblogs.com/xumBlog/p/12708281.html
