random
description
Syntax
DOUBLE random()
返回0-1之间的随机数。
DOUBLE random(DOUBLE seed)
返回0-1之间的随机数，以seed作为种子。
BIGINT random(BIGINT a, BIGINT b)
返回a-b之间的随机数，a必须小于b。
别名：rand
注意：所有参数必须为常量。
example
mysql> select random();
+---------------------+
| random() |
+---------------------+
| 0.35446706030596947 |
+---------------------+
mysql> select rand(1.2);
+---------------------+
| rand(1) |
+---------------------+
| 0.13387664401253274 |
+---------------------+
1 row in set (0.13 sec)
mysql> select rand(1.2);
+---------------------+
| rand(1) |
+---------------------+
| 0.13387664401253274 |
+---------------------+
1 row in set (0.11 sec)
mysql> select rand(-20, -10);
+------------------+
| random(-20, -10) |
+------------------+
| -13 |
+------------------+
1 row in set (0.10 sec)keywords
RANDOM, RAND