摘要：
应用在使用过程中发现数据表中有一些重复记录，现需要根据 taobao_nick, taobao_id 来过滤出重复记录并删除，保留其中一条记录即可。1. 首先使用查询语句检查一下重复记录数select taobao_nick, taobao_id, count(*) from user group by taobao_nick, taobao_id having count(*) > 1;2. 使用以下语句删除数据 DB2和Oracle:delete from user where id in (select max(ID) as id from user group by taobao 阅读全文
摘要：
Tomcat Log 中有以下异常May 31, 2012 11:54:25 AM org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler processSEVERE: Error reading request, ignoredjava.lang.OutOfMemoryError: GC overhead limit exceededException in thread "http-80-43" java.lang.NullPointerException at java.util.concurre 阅读全文