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。
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。更多详情敬请关注亿速云行业资讯频道。