如果在创建新表时不包括VARCHAR的大小，MySQL是否可以正常工作？
不，查询将无法进行。让我们创建相同的场景并检查错误-
mysql> create table DemoTable1821
(
Id int,
FirstName varchar,
LastName varchar
);
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 ',
LastName varchar
)' at line 4要消除上述错误，您需要提供varchar(10)的大小。让我们首先创建一个表-
mysql> create table DemoTable1821
(
Id int,
FirstName varchar(10),
LastName varchar(10)
);使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1821 values(1,'John','Smith'); mysql> insert into DemoTable1821 values(2,'John','Doe'); mysql> insert into DemoTable1821 values(3,'Adam','Smith');
使用select语句显示表中的所有记录-
mysql> select * from DemoTable1821;
这将产生以下输出-
+------+-----------+----------+ | Id | FirstName | LastName | +------+-----------+----------+ | 1 | John | Smith | | 2 | John | Doe| | 3 | Adam | Smith | +------+-----------+----------+ 3 rows in set (0.00 sec)