mysql 输出九九乘法表

以下是使用MySQL输出九九乘法表的方法：

SELECT CONCAT_WS(' ', a.num, '*', b.num, '=', a.num * b.num) AS result
FROM
(SELECT 1 AS num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) AS a
CROSS JOIN
(SELECT 1 AS num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) AS b
WHERE a.num >= b.num
ORDER BY a.num, b.num;

该方法使用了MySQL的SELECT语句和CROSS JOIN语句，首先创建了两个子查询，分别生成1到9的数字序列，然后使用CROSS JOIN将它们组合成一个九九乘法表。最后使用CONCAT_WS函数将结果拼接成字符串，并按照数字大小排序输出。

相关问题

如何在数据库输出九九乘法表

假设你使用的是MySQL数据库，可以通过以下SQL语句输出九九乘法表：

SELECT CONCAT_WS('', GROUP_CONCAT(CONCAT_WS('*', t1.num, t2.num) ORDER BY t2.num SEPARATOR '\t'), '\n')
FROM (
  SELECT 1 AS num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t1
JOIN (
  SELECT 1 AS num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9
) t2
ON t1.num >= t2.num
GROUP BY t1.num;

这条SQL语句使用了两个子查询，分别生成了1到9的数字序列，并用JOIN连接起来。然后使用GROUP_CONCAT函数将每一行的乘法表达式连接成一个字符串，再用CONCAT_WS函数将字符串拼接成一行，最后用GROUP BY将每一行分组输出。

mysql实现99乘法表

以下是使用MySQL实现99乘法表的两种方法：

1.使用SELECT语句实现：

SELECT CONCAT_WS(' ', a.num, 'x', b.num, '=', a.num*b.num) AS result
FROM
(SELECT 1 AS num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) AS a
CROSS JOIN
(SELECT 1 AS num UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) AS b
WHERE a.num >= b.num;

2.使用CREATE PROCEDURE语句创建存储过程实现：

CREATE PROCEDURE multiplication_table()
BEGIN
    DECLARE i INT DEFAULT 1;
    DECLARE j INT DEFAULT 1;
    DECLARE result VARCHAR(50);
    WHILE i <= 9 DO
        WHILE j <= i DO
            SET result = CONCAT_WS(' ', j, 'x', i, '=', i*j);
            SELECT result;
            SET j = j + 1;
        END WHILE;
        SET j = 1;
        SET i = i + 1;
    END WHILE;
END;

然后执行以下语句调用存储过程：

CALL multiplication_table();