1、select kd.CREATEUSERID as userid,kd.LOCATION,kd.createtime as location from KT_DEVICESTRACK kd where rownum=1 order by kd.createtime2、SELECT * FROM ( SELECT *,ROWNUM rn FROM t ORDER BY date_col DESC ) WHERE rn = 13、update cg_berthtrace cg set cg.chagedtime=sysdate,cg.parkduration=(cg.chagedtime-cg.createtime)*24*60,cg.berthstatus=11where cg.berthno in(select po.bowei from pda_order po where p...
编写一个 SQL 查询，获取 Employee 表中第 n 高的薪水（Salary）。 +----+--------+| Id | Salary |+----+--------+| 1 | 100 || 2 | 200 || 3 | 300 |+----+--------+ 例如上述 Employee 表，n = 2 时，应返回第二高的薪水 200。如果不存在第 n 高的薪水，那么查询应返回 null。 +------------------------+| getNthHighestSalary(2) |+------------------------+| 200 |+------------------------+ 网上有很多关于mysql的编写方...