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MySQL查询更新具有相同值的每个替代行字符串？

2024-05-14 16:36:05 401

让我们首先创建一个表-

mysql> create table DemoTable
   -> (
   -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   -> Subject varchar(100)
   -> );

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable(Subject) values('C');

mysql> insert into DemoTable(Subject) values('MongoDB');

mysql> insert into DemoTable(Subject) values('Java');

mysql> insert into DemoTable(Subject) values('MongoDB');

mysql> insert into DemoTable(Subject) values('Python');

mysql> insert into DemoTable(Subject) values('MongoDB');

使用select语句显示表中的所有记录-

mysql> select *from DemoTable;

输出结果

+----+---------+
| Id | Subject |
+----+---------+
| 1  | C       |
| 2  | MongoDB |
| 3  | Java    |
| 4  | MongoDB |
| 5  | Python  |
| 6  | MongoDB |
+----+---------+
6 rows in set (0.00 sec)

这是每隔第二行字符串更新的查询-

mysql> update DemoTable set Subject=replace(Subject,'MongoDB','MySQL') where Id%2=0;
Rows matched: 3 Changed: 3 Warnings: 0

让我们检查表中的所有记录-

mysql> select *from DemoTable;

输出结果

+----+---------+
| Id | Subject |
+----+---------+
| 1  | C       |
| 2  | MySQL   |
| 3  | Java    |
| 4  | MySQL   |
| 5  | Python  |
| 6  | MySQL   |
+----+---------+
6 rows in set (0.00 sec)

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MySQL查询更新具有相同值的每个替代行字符串？

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