MySQL的隨機整數

Original post: http://anothermysqldba.blogspot.com/2014/06/mysql-random-integers.html

這是不以任何手段的一項新功能，但它是一個問題，我也碰巧看到彈出飄飛。 所以，一個簡單的例子是下面的。 

到MySQL中生成一個隨機整數您可以使用地板和蘭德功能。 MySQL手冊此文件在這裡：http://dev.mysql.com/doc/refman/5.5/en/mathematical-functions.html＃function_rand 

“ 為了獲得範圍內的隨機整數R I <= R <J2，使用表達式FLOOR（i + RAND（）*（十-一）） “ 

所以，舉個例子： 

> SET @I = 3; # lower range 
> SET @J = 43 - @I; # max range minus lower range 

> SELECT FLOOR( @I + (RAND() * @J )) as lottery_numbers\G 
*************************** 1. row *************************** 
lottery_numbers: 4 
1 row in set (0.00 sec) 
> SELECT FLOOR( @I + (RAND() * @J )) as lottery_numbers\G 
*************************** 1. row *************************** 
lottery_numbers: 8 
1 row in set (0.00 sec 
> SELECT FLOOR( @I + (RAND() * @J )) as lottery_numbers\G 
*************************** 1. row *************************** 
lottery_numbers: 15 
1 row in set (0.00 sec 
> SELECT FLOOR( @I + (RAND() * @J )) as lottery_numbers\G 
*************************** 1. row *************************** 
lottery_numbers: 16 
1 row in set (0.00 sec 
> SELECT FLOOR( @I + (RAND() * @J )) as lottery_numbers\G 
*************************** 1. row *************************** 
lottery_numbers: 23 
1 row in set (0.00 sec 
> SELECT FLOOR( @I + (RAND() * @J )) as lottery_numbers\G 
*************************** 1. row *************************** 
lottery_numbers: 42 
1 row in set (0.00 sec