更新 MySQL 表中单个列的最佳方法是什么?
mysqlmysqli database更新于 2024/1/9 16:45:00
要更新单个列，请使用 UPDATE 和 SET，语法如下 −
update yourTableName set yourColumnName=yourValue;
首先我们创建一个表 −
mysql> create table DemoTable1873 ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(20) ); Query OK, 0 rows affected (0.00 sec)
使用 insert 插入命令在表中插入一些记录 −
mysql> insert into DemoTable1873(FirstName) values('John');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1873(FirstName) values('Adam');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1873(FirstName) values('David');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1873(FirstName) values('Sam');
Query OK, 1 row affected (0.00 sec)
使用 select 语句显示表中的所有记录 −
mysql> select * from DemoTable1873 ;
这将产生以下输出 −
+----+-----------+ | Id | FirstName | +----+-----------+ | 1 | John | | 2 | Adam | | 3 | David | | 4 | Sam | +----+-----------+ 4 rows in set (0.00 sec)
这是更新 MySQL 表中单个列的查询 −
mysql> update DemoTable1873 set FirstName='Robert'; Query OK, 4 rows affected (0.00 sec) Rows matched: 4 Changed: 4 Warnings: 0
让我们再次检查表记录 −
mysql> select * from DemoTable1873 ;
这将产生以下输出 −
+----+-----------+ | Id | FirstName | +----+-----------+ | 1 | Robert | | 2 | Robert | | 3 | Robert | | 4 | Robert | +----+-----------+ 4 rows in set (0.00 sec)
