MySQLint（4）类型的值范围是多少呢？
mysql> create table t1 (a int(4));
Query OK, 0 rows affected (0.14 c)
mysql> inrt into t1 values(15652);
Query OK, 1 row affected (0.06 c)春联对联大全
mysql> inrt into t1 values(156522);
Query OK, 1 row affected (0.05 c)仙灵女巫
mysql> inrt into t1 values(156********);
ERROR 1264 (22003): Out of range value adjusted for column 'a' at row 1
月季和玫瑰mysql> inrt into t1 values(1565222);
幸福的时刻Query OK, 1 row affected (0.06 c)
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网络错误651
mysql> inrt into t1 values(15652222);
Query OK, 1 row affected (0.08 c)
mysql> inrt into t1 values(156522222);
Query OK, 1 row affected (0.05 c)
mysql> inrt into t1 values(1565222222);
Query OK, 1 row affected (0.03 c)
mysql> inrt into t1 values(1565222222)2;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that
corresponds to your MySQL rver version for the right syntax to u near '2' at
line 1
mysql>
为什么int(4)类型的字段可以插⼊9位的数字呢？
int(n)中不论n指定为多少，范围都⼀样-2~31~2^31-1，都能插⼊9位数字。n只是⽤来控制显⽰⽽已，如果为低脂食物
int(4)，插⼊⼀个1，显⽰时也会⽤空格补齐到4个字节
请问所有mysql中的数据类型中的(n)都是表⽰显⽰位数吗？
并⾮如此，NUMERIC（4）就限定了取值范围，超过4位就不允许写⼊了。因此如果你想限定数字的取值范
围，最好是⽤NUMERIC来定义。
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