您好,登錄后才能下訂單哦!
本篇文章給大家分享的是有關(guān)MySQL中如何刪除表重復(fù)記錄,小編覺得挺實(shí)用的,因此分享給大家學(xué)習(xí),希望大家閱讀完這篇文章后可以有所收獲,話不多說,跟著小編一起來看看吧。
創(chuàng)建實(shí)驗(yàn)表student表數(shù)據(jù):
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中如何刪除表重復(fù)記錄,小編相信有部分知識(shí)點(diǎn)可能是我們?nèi)粘9ぷ鲿?huì)見到或用到的。希望你能通過這篇文章學(xué)到更多知識(shí)。更多詳情敬請(qǐng)關(guān)注億速云行業(yè)資訊頻道。
免責(zé)聲明:本站發(fā)布的內(nèi)容(圖片、視頻和文字)以原創(chuàng)、轉(zhuǎn)載和分享為主,文章觀點(diǎn)不代表本網(wǎng)站立場(chǎng),如果涉及侵權(quán)請(qǐng)聯(lián)系站長郵箱:is@yisu.com進(jìn)行舉報(bào),并提供相關(guān)證據(jù),一經(jīng)查實(shí),將立刻刪除涉嫌侵權(quán)內(nèi)容。