一个有趣的SQL:根据登录日志,求系统无人登录时间
2015-09-12 01:20
381 查看
今天MySQL群里有人发了这个问题:
![](http://img.blog.csdn.net/20150911235621689?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center)
建立测试数据和样表:
SQL:
建立测试数据和样表:
SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for `adtimelog` -- ---------------------------- DROP TABLE IF EXISTS `adtimelog`; CREATE TABLE `adtimelog` ( `Aname` varchar(12) CHARACTER SET utf8 DEFAULT NULL, `LITime` timestamp NULL DEFAULT NULL, `LOTime` timestamp NULL DEFAULT NULL, `DTime` timestamp NULL DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- ---------------------------- -- Records of adtimelog -- ---------------------------- INSERT INTO `adtimelog` VALUES ('甲', '2015-08-13 08:30:00', '2015-08-13 09:30:00', '2015-08-13 00:00:00'); INSERT INTO `adtimelog` VALUES ('甲', '2015-08-13 09:40:00', '2015-08-13 10:00:00', '2015-08-13 00:00:00'); INSERT INTO `adtimelog` VALUES ('甲', '2015-08-13 08:30:00', '2015-08-13 11:30:00', '2015-08-13 00:00:00'); INSERT INTO `adtimelog` VALUES ('丁', '2015-08-13 00:30:00', '2015-08-13 01:30:00', '2015-08-13 00:00:00'); INSERT INTO `adtimelog` VALUES ('丁', '2015-08-13 02:30:00', '2015-08-13 07:30:00', '2015-08-13 00:00:00');
SQL:
select '2015-08-13 00:00:00',min(LITime) from ADTimeLog where DTime='2015/8/13' UNION ALL select distinct a.LOTime,min(b.LITime) from (select LITime,LOTime from ADTimeLog where DTime='2015/8/13' order by LITime ) a, (select LITime,LOTime from ADTimeLog where DTime='2015/8/13' order by LITime limit 1,99999) b where a.LOTime<b.LITime GROUP BY a.LOTime UNION ALL select max(LOTime),'2015-08-13 23:59:59' from ADTimeLog where DTime='2015/8/13'
相关文章推荐
- 删除mysql的root用户恢复方法
- MySQL的安装配置
- MySql中IFNULL、CONCAT和INSERT INTO...SELECT FROM多表复制的介绍
- T-SQL 函数概述
- SQL Server2014 哈希索引原理
- mysql设置外部ip访问
- SQL Server 收缩日志
- 最新手机号段归属地数据库 2018年3月版 382140条记录
- FMDB Sqlite Unknown error calling sqlite3_step (5:
- Oracle触发器创建自增主键
- mysql主键自增
- Mysql 影响行数
- Postgresql入门
- sqlite 数据库的实践,事务和升级数据库
- mysql小记
- Navicat 2003-can't connect to MYSQL server on 'localhost'(10061)
- oracle中删除表空间提示ORA-00604和ORA-38301
- 下载安装oracle11g
- Can t connect to MySQL server on 解决方法
- 数据库 之 入门篇