MySQL - 使用最后12位数的随机值更新已连接列

Question

我有一个名为Joined（varchar（50））的MYSQL列，其值为13个数字如何实现该查询？

UPDATE `users` SET `joined` = 153ZZZZZZZZZZ

Answer 1

尝试：

UPDATE `users` 
SET `joined` = CONCAT('153', FLOOR(RAND()* 9000000000) + 1000000000)

Answer 2

你可以生成md（）随机字符串，例如：

UPDATE `users` 
SET `joined` = concat('153',SUBSTRING(MD5(RAND()) FROM 1 FOR 10) )

要么

UPDATE `users` 
SET `joined` = concat('153',SUBSTRING(MD5(RAND()) FROM 1 FOR 6), 
                            SUBSTRING(MD5(RAND()) FROM 1 FOR 4) )

或者，如果您只需要数字，则可以使用

UPDATE `users` 
SET `joined` = concat('153',CAST(rand()*1000000 as UNSIGNED), 
                            CAST(rand()*10000 as UNSIGNED) )

对于具有短字符串的行，您可以使用大小写来根据需要调整代码

UPDATE `users` 
SET `joined` = case when length(joined)= 14 then
                concat('153',CAST(rand()*10000000 as UNSIGNED), 
                            CAST(rand()*10000 as UNSIGNED) )
                    when  length(joined)= 13 then
                concat('153',CAST(rand()*1000000 as UNSIGNED), 
                            CAST(rand()*10000 as UNSIGNED) )
                .....
                end