数据库内容，随机编了一些数据，其中认为两个字段Name、Address1一致为重复记录，保留其中一条

  1. 删除两个字段Name、Address1一致重　　复的记录，保留一条：
    • 找出，（ 如果没有第三行，会有什么问题呢？可将示例数据中 ID 为4的行，Name字段改为Tom测试一下）
1 select * from tableabc
2 where Name in( select Name from tableabc group by Name, Address1 having count(Name) > 1)
3 and Address1 in( select Address1 from tableabc group by Name, Address1 having count(Address1) > 1)
    • 删除
1 select * from tableabc 
2 where Name in( select Name from tableabc group by Name, Address1 having count(Name) > 1)
3 and Address1 in( select Address1 from tableabc group by Name, Address1 having count(Address1) > 1)
4 and ID not in(select max(ID) from tableabc group by Name,Address1 having count(Name) > 1 )