如何在MySQL中交换特定的字段值?
让我们首先创建一个表-
mysql> create table DemoTable(
Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
Number1 int,
Number2 int
);
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable(Number1,Number2) values(10,30);mysql> insert into DemoTable(Number1,Number2) values(60,50);
mysql> insert into DemoTable(Number1,Number2) values(110,100);
使用select语句显示表中的所有记录-
mysql> select *from DemoTable;
这将产生以下输出-
+----+---------+---------+| Id | Number1 | Number2 |
+----+---------+---------+
| 1 | 10 | 30 |
| 2 | 60 | 50 |
| 3 | 110 | 100 |
+----+---------+---------+
3 rows in set (0.00 sec)
现在让我们在MySQL中交换特定的字段值。在这里,我们交换ID为2的字段“ Number1 ”和“ Number2 ”-
mysql> update DemoTableset Number1=(@temporaryVariable:=Number1),
Number1=Number2,
Number2=@temporaryVariable
where Id=2;
Rows matched: 1 Changed: 1 Warnings: 0
让我们再次检查表记录-
mysql> select *from DemoTable;
这将产生以下输出-
+----+---------+---------+| Id | Number1 | Number2 |
+----+---------+---------+
| 1 | 10 | 30 |
| 2 | 50 | 60 |
| 3 | 110 | 100 |
+----+---------+---------+
3 rows in set (0.00 sec)
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