mysql数据库删除重复数据并保留一条数据

先看下表结构

1.首先查询重复数据的id(这里面的movie_id有重复的)

SELECT id from movie GROUP BY movie_id HAVING COUNT(movie_id)>1 （这里默认好像是查询最小的id）

2.查询重复的movie_id对应的id

select id from movie where movie_id in (SELECT movie_id from movie GROUP BY movie_id HAVING COUNT(movie_id)>1)(这里查询movie_id对应全部的id)

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3.从总的id里面减去重复数据的最小id即为我们要删除的id的集合

然后我准备这样写:

delete from movie where id in 

(select id from movie where movie_id in (SELECT movie_id from movie GROUP BY movie_id HAVING COUNT(movie_id)>1)) 

and id not in (SELECT id from movie GROUP BY movie_id HAVING COUNT(movie_id)>1)

然后就报错了,查资料好像是mysql数据库里select和delete不能一起用,网上有种方法是构建临时表储存被删除的id，然后再删除,感觉有点麻烦。

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最后我是用python脚本删除重复数据的,用列表存储被删除的id，构建sql语句删除就好了

具体代码如下:

import pymysql

result=[]
conn=pymysql.connect(host='localhost',user='root',password='password',db='web',charset='utf8')
cur=conn.cursor()
sql='''
select id from movie where movie_id in (SELECT movie_id from movie GROUP BY movie_id HAVING COUNT(movie_id)>1) and id not in (SELECT id from movie GROUP BY movie_id HAVING COUNT(movie_id)>1)
'''
cur.execute(sql)
for each in cur.fetchall():
    result.append(each[0])
for each in result:
    sql='delete from movie_info where id=%d'%each
    cur.execute(sql)
conn.commit()
conn.close()