我们可以在CREATE TABLE语句中使用“何时”作为列名吗?
在开始之前,让我们尝试使用CREATETABLE语句将“when”设置为列名-
create table DemoTable693( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(100), When datetime );
这将产生以下输出。错误将是可见的:
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'When datetime at line 5
您需要使用反引号将保留字换行,例如`when`。让我们首先创建一个表并实现它:
create table DemoTable693 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(100), `When` datetime );
使用insert命令在表中插入一些记录:
insert into DemoTable693(StudentName,`When`) values('Chris',NOW()); insert into DemoTable693(StudentName,`When`) values('Robert',CURDATE());
使用select语句显示表中的所有记录-
select *from DemoTable693;
这将产生以下输出-
+-----------+-------------+---------------------+ | StudentId | StudentName | When | +-----------+-------------+---------------------+ | 1 | Chris | 2019-07-21 18:57:19 | | 2 | Robert | 2019-07-21 00:00:00 | +-----------+-------------+---------------------+ 2 rows in set (0.00 sec)