mysql数据类型-小数
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decimal[(m,d])] [unsigned] [zerofill]
-
unsigned 表示无符号
zerofill
仅用于显示,
当不满足时,按照左边补0
准确的小数值,m是数字总个数(负号不算),d是小数点后个数。 m最大值为65,d最大值为30。
例如:
create table L2(
id int not null primary key auto_increment,
salary decimal(8,2)
)default charset=utf8;
mysql> create table L2(id int not null primary key auto_increment,salary decimal(8,2))default charset=utf8;
Query OK, 0 rows affected (0.03 sec)
mysql> insert into L2(salary) values(1.28);
Query OK, 1 row affected (0.01 sec)
mysql> insert into L2(salary) values(5.289);
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> insert into L2(salary) values(5.282);
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> insert into L2(salary) values(512132.28);
Query OK, 1 row affected (0.00 sec)
mysql> insert into L2(salary) values(512132.283);
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> select * from L2;
+----+-----------+
| id | salary |
+----+-----------+
| 1 | 1.28 |
| 2 | 5.29 |
| 3 | 5.28 |
| 4 | 512132.28 |
| 5 | 512132.28 |
+----+-----------+
5 rows in set (0.00 sec)
mysql> insert into L2(salary) values(5121321.283); --这里插入数据时会报错,在创建表字段时,规定了总长度为8位(小数据点前面和后面共8位)
ERROR 1264 (22003): Out of range value for column 'salary' at row 1
mysql>
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FLOAT[(M,D)] [UNSIGNED] [ZEROFILL]
单精度浮点数,非准确小数值,m是数字总个数,d是小数点后个数。
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DOUBLE[(M,D)] [UNSIGNED] [ZEROFILL]
双精度浮点数(非准确小数值),m是数字总个数,d是小数点后个数。