以為通過命令直接刪除就可以了，總是報錯：

delete from test


where name in(select name from test as t having count(name)>1)

發現在這隻能建立臨時表格,方法1設計可行：

1. 首先先建立一個臨時表,然後將author表中無重複的資料拎出來，放進臨時表中。
create temporary table 表名
select distinct id,name,password 
from author

然後將author表中的記錄全部刪除。
delete from author

最後將臨時表中的記錄插入author表中
insert into author (id,name,password)

2.方法2直接使用語句：

delete from test
where name in(select t.name from (select name from test) as t having count(t.name)>1)
and name not in(select min(id) from(select id,name from test group by name)as tt having count(tt.name)>1)

發現總是刪錯資料，還未得到驗證這種查詢是否可行