MySQL中如何删除表重复记录

本篇文章给大家分享的是有关MySQL中如何删除表重复记录,小编觉得挺实用的,因此分享给大家学习,希望大家阅读完这篇文章后可以有所收获,话不多说,跟着小编一起来看看吧。

10多年的叙州网站建设经验,针对设计、前端、开发、售后、文案、推广等六对一服务,响应快,48小时及时工作处理。网络营销推广的优势是能够根据用户设备显示端的尺寸不同,自动调整叙州建站的显示方式,使网站能够适用不同显示终端,在浏览器中调整网站的宽度,无论在任何一种浏览器上浏览网站,都能展现优雅布局与设计,从而大程度地提升浏览体验。创新互联从事“叙州网站设计”,“叙州网站推广”以来,每个客户项目都认真落实执行。

创建实验表student表数据:
mysql> use test
Database changed
mysql> create table student (id int,name varchar(10));
Query OK, 0 rows affected (1.67 sec)

mysql> insert into student values (11,'aa');
Query OK, 1 row affected (0.26 sec)


mysql> insert into student values (12,'aa');
Query OK, 1 row affected (0.07 sec)


mysql> insert into student values (13,'aa');
Query OK, 1 row affected (0.12 sec)


mysql> insert into student values (14,'aa');
Query OK, 1 row affected (0.11 sec)


mysql> insert into student values (15,'bb');
Query OK, 1 row affected (0.19 sec)


mysql> insert into student values (16,'bb');
Query OK, 1 row affected (0.14 sec)


mysql> insert into student values (17,'cc');
Query OK, 1 row affected (0.15 sec)


mysql> select * from student;
+------+------+
| id   | name |
+------+------+
|   11 | aa   |
|   12 | aa   |
|   13 | aa   |
|   14 | aa   |
|   15 | bb   |
|   16 | bb   |
|   17 | cc   |
+------+------+
7 rows in set (0.22 sec)


方法1:
mysql>  create temporary table temp as select min(id),name from student group by name;
Query OK, 3 rows affected (0.18 sec)
Records: 3  Duplicates: 0  Warnings: 0


mysql> truncate table student;
Query OK, 0 rows affected (0.40 sec)


mysql> insert into student select * from temp;
Query OK, 3 rows affected (0.11 sec)
Records: 3  Duplicates: 0  Warnings: 0


mysql> select * from student;
+------+------+
| id   | name |
+------+------+
|   11 | aa   |
|   15 | bb   |
|   17 | cc   |
+------+------+
3 rows in set (0.00 sec)


mysql> drop temporary table temp;
Query OK, 0 rows affected (0.17 sec)


方法2:
mysql> create temporary table temp as select min(id) as MINID from student group by name;
Query OK, 3 rows affected (0.24 sec)
Records: 3  Duplicates: 0  Warnings: 0


mysql> delete from student where id not in (select minid from temp);
Query OK, 4 rows affected (0.07 sec)


mysql> select * from student;
+------+------+
| id   | name |
+------+------+
|   11 | aa   |
|   15 | bb   |
|   17 | cc   |
+------+------+
3 rows in set (0.00 sec)


方法3:
mysql> delete from student where id not in (select minid from (select min(id) as minid from student
group by name) b);
Query OK, 4 rows affected (0.19 sec)


mysql> select * from student;
+------+------+
| id   | name |
+------+------+
|   11 | aa   |
|   15 | bb   |
|   17 | cc   |
+------+------+
3 rows in set (0.00 sec)

以上就是MySQL中如何删除表重复记录,小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注创新互联行业资讯频道。


当前题目:MySQL中如何删除表重复记录
文章链接:http://ybzwz.com/article/ggipij.html