數據庫內容，隨機編了一些數據，其中認為兩個字段Name、Address1一致為重復記錄，保留其中一條

1. 刪除兩個字段Name、Address1一致重　　復的記錄，保留一條：
   • 找出，（ 如果沒有第三行，會有什麽問題呢？可將示例數據中 ID 為4的行，Name字段改為Tom測試一下）

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)

• • 刪除

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 )

數據清理——刪除多個字段重復的記錄