1、原理讲解-可直接看2

筛选出最新的

SELECT *  
FROM (  SELECT t.*,  ROW_NUMBER() OVER (PARTITION BY LOCALAUTHID ORDER BY LASTUPDATETIME DESC) AS rn  FROM USER_LOCALAUTH_STATE t  
) t  
WHERE t.rn = 1;

解释：

这个序号是基于[LOCALAUTHID]字段进行分区的（即每个[LOCALAUTHID]值都是一个新的分区），并且在每个分区内部，行是按照LASTUPDATETIME字段降序排列的

2、在重复数据取最新的

SELECT *  
FROM (  SELECT t.*,ROW_NUMBER() OVER (PARTITION BY LOCALAUTHID ORDER BY LASTUPDATETIME DESC) AS rn  FROM    (-- 筛选存在重复的数据，count(LOCALAUTHID) > 1select * from USER_LOCALAUTH_STATEwhere LOCALAUTHID	in (SELECT LOCALAUTHIDFROM USER_LOCALAUTH_STATE WHERE STATE = 1 AND BUSINESSTYPE=1group by LOCALAUTHID having count(LOCALAUTHID) > 1)) t) rt  
WHERE rt.rn = 1;

3、若要删除不满足条件

在2的基础上，通过[LOCALAUTHID]查询，并删除ID不再2中的