mysql数学相关函数

### abs 绝对值
mysql> select abs(-10) from dual;
+----------+
| abs(-10) |
+----------+
|       10 |
### bin 十进制转二进制
mysql> select bin(10) from dual;
+---------+
| bin(10) |
+---------+
| 1010    |
+---------+
### ceiling 向上取整
mysql> select ceiling(11.1) from dual;
+---------------+
| ceiling(11.1) |
+---------------+
|            12 |
+---------------+
### conv 进制转换
mysql> select conv(11,10,2) from dual;
+---------------+
| conv(11,10,2) |
+---------------+
| 1011          |
+---------------+
### floor 向下取整
mysql> select floor(11.9) from dual;
+-------------+
| floor(11.9) |
+-------------+
|          11 |
+-------------+
### format 保留小数位数
mysql> select format(11.97389274,4) from dual;
+-----------------------+
| format(11.97389274,4) |
+-----------------------+
| 11.9739               |
+-----------------------+
### hex 转16进制
mysql> select hex(11) from dual;
+---------+
| hex(11) |
+---------+
| B       |
+---------+
### least 求最小值
mysql> select least(11,15,17,19) from dual;
+--------------------+
| least(11,15,17,19) |
+--------------------+
|                 11 |
+--------------------+
### mod 求余
mysql> select mod(10,3) from dual;
+-----------+
| mod(10,3) |
+-----------+
|         1 |
### rand() 随机数在0，1之间，给种子后数不变
mysql> select rand(),rand(10),rand(10) from dual;
+--------------------+--------------------+--------------------+
| rand()             | rand(10)           | rand(10)           |
+--------------------+--------------------+--------------------+
| 0.7603708196062323 | 0.6570515219653505 | 0.6570515219653505 |
+--------------------+--------------------+--------------------+
1 row in set (0.00 sec)