数据中现有大量重复数据，我要删除最老的数据 比如name,time两个字段 a,2009-12-30 20:12:43 a,2010-1-10 3:19:42 a,2010-1-15 13:39:12 只保留最近的一条（第三条）记录。谁能说下SQL应该怎么写呢？谢谢。 老兄，你误会了吧。a是字段内容， 字段名name,time a,2009-12-30 20:12:43 a,2010-1-10 3:19:42 a,2010-1-15 13:39:12 执行删除后结束为 a,2010-1-15 13:39:12 DELETE A from A LEFT JOIN (SELECT NAME,MAX(TIME) AS MA from A GROUP BY NAME) B ON A.NAME=B.NAME AND A.TIME=B.MA WHERE B.NAME IS NULL delete from mytable t where exists (select 1 from mytable where a=t.a and `time`>a.`time`); delete a from table1 a left join (select name,max(time) as time from table1 group by name) b on a.name=b.name and a.time=b.time where b.name is null
我用的是连接池做的，配连接池的方法应该没有错，为什就是出现这种问题 javax.servlet.ServletException: javax.naming.NameNotFoundException: No object bound to name java:comp/env/test 请问大侠们这是� ......
