MySQL 如何在存储过程中生成5个随机数

要生成随机数，在MySQL中使用ORDER BY RAND()函数。首先创建一个表——

mysql> create table DemoTable (Value int);
Query OK, 0 rows affected (0.76 sec)

使用insert命令向表中插入一些记录——

mysql> insert into DemoTable values(89);
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable values(98);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values(10);
Query OK, 1 row affected (0.34 sec)
mysql> insert into DemoTable values(78);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values(75);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values(76);
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable values(74);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable values(99);
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable values(101);
Query OK, 1 row affected (0.15 sec)

使用select语句显示表中的所有记录——

mysql> select *from DemoTable;

这将产生以下输出——

+-------+
| Value |
+-------+
| 89    |
| 98    |
| 10    |
| 78    |
| 75    |
| 76    |
| 74    |
| 99    |
| 101   |
+-------+
9 rows in set (0.00 sec)

以下是在MySQL存储过程中生成5个随机数的查询——

mysql> DELIMITER //
mysql> CREATE PROCEDURE generate_Random5Numbers()
   BEGIN
      SELECT GROUP_CONCAT(Value SEPARATOR '/')
      FROM ( SELECT Value
         FROM ( SELECT Value
            FROM DemoTable
            WHERE Value BETWEEN 10 AND 100
           ORDER BY RAND()
           LIMIT 5) Ascending_Order
         ORDER BY Value) 5Values;
   END
   //
Query OK, 0 rows affected (0.31 sec)
mysql> DELIMITER ;

使用call命令调用存储过程。

mysql> call generate_Random5Numbers();

这将产生以下输出——

+-----------------------------------+
| GROUP_CONCAT(Value SEPARATOR '/') |
+-----------------------------------+
| 89/74/78/99/10                    |
+-----------------------------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.02 sec)

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