使用递归 MySQL 插入唯一随机数

Question

我想在不使用过程的情况下使用唯一的随机数填充 table。

我试过使用回复来做到这一点，但没有成功。

我正在尝试做的是类似这样的事情，但要验证数字没有重复：

INSERT into table (row1,row2)
WITH RECURSIVE
cte AS ( SELECT 0 num, LPAD(FLOOR(RAND() * 99999999),8,0) random_num 
         UNION ALL 
         SELECT num+1, LPAD(FLOOR(RAND() * 99999999),8,0) random_num 
         FROM cte WHERE num < 100000-1)
SELECT random_num, null
FROM cte;

在上面的示例中，我能够生成随机值并插入它们，但没有验证数字是否重复。

我试过这样做：

INSERT into table (row1,row2)
WITH RECURSIVE
cte AS ( SELECT 0 num, LPAD(FLOOR(RAND() * 99999999),8,0) random_num 
         UNION ALL 
         SELECT num+1, LPAD(FLOOR(RAND() * 99999999),8,0) random_num 
         FROM cte WHERE num < 100000-1 AND random_num NOT IN (SELECT random_num FROM cte WHERE random_num IS NOT NULL))
SELECT random_num, null
FROM cte;

但是 where 情况下的条件 AND random_num NOT IN (SELECT random_num FROM cte WHERE random_num IS NOT NULL) 会导致 SQL Error [4008] [HY000]: Restrictions imposed on recursive definitions are violated for table 'cte'

有什么建议吗？谢谢！

Answer 1

如果您有 table - 任何 table - 例如100 行，那么你可以生成 0 到 99999999 之间的百万个不同的随机数，如下所示：

select distinct floor(rand() * 100000000)
from t as t0, t as t1, t as t2
limit 1000000

请注意，由于 distinct，您将需要生成更多的行，以便在 distinct 之后获得所需的行数。

Answer 2

这可能是一个选项。生成所有可能的值，随机排序并获取所需数量的条目。

CREATE TABLE random_data (
  row1 INT PRIMARY KEY AUTO_INCREMENT,
  row2 VARCHAR(10) NOT NULL,
  UNIQUE KEY _Idx1 ( row2 )
);

INSERT INTO random_data (row2)
SELECT LPAD(num, 8, 0)
FROM (
  SELECT h * 10000000 + g * 1000000 + f * 100000 + e * 10000 + d * 1000 + c * 100 + b * 10 + a AS num
  FROM (SELECT 0 a 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) ta
  JOIN (SELECT 0 b 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) tb
  JOIN (SELECT 0 c 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) tc
  JOIN (SELECT 0 d 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) td
  JOIN (SELECT 0 e 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) te
  JOIN (SELECT 0 f 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) tf
  JOIN (SELECT 0 g 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) tg
  JOIN (SELECT 0 h 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) th
) n
ORDER BY RAND()
LIMIT 100000;

使用递归 MySQL 插入唯一随机数

Insert unique random number with recursive MySQL

mysql

recursion

multiple-value

unique-values