mysql创建水仙花数

MySQL 创建水仙花数

水仙花数是指一个三位数，它的每个位上的数字的三次幂之和等于它本身。例如，153是一个水仙花数，因为 1^3 + 5^3 + 3^3 =153。下面我们通过MySQL实现水仙花数的创建。

创建一个保存水仙花数的表flower_num：

CREATE TABLE flower_num (num INT(3) PRIMARY KEY,is_flower TINYINT(1));
    

然后使用以下INSERT语句创建水仙花数：

INSERT INTO flower_num (num, is_flower)SELECT i.num, IF(SUM(POW(SUBSTRING(i.num, 1, 1), 3), POW(SUBSTRING(i.num, 2, 1), 3), POW(SUBSTRING(i.num, 3, 1), 3)) = i.num, 1, 0) AS is_flowerFROM (SELECT 100 + t3 * 100 + t2 * 10 + t1 AS numFROM (SELECT 0 AS t1 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t1CROSS JOIN (SELECT 0 AS t2 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t2CROSS JOIN (SELECT 0 AS t3 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t3) iGROUP BY i.num;
    

执行完以上代码后，flower_num表中就会存储从100到999之间的所有水仙花数。我们可以使用以下查询语句验证结果：

SELECT num FROM flower_num WHERE is_flower = 1;
    

通过以上操作，我们成功地使用MySQL创建了水仙花数。

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