在 MYSQL 中将随机数插入表中

2021-12-30 00:00:00 random row count mysql

我正在尝试计算表中的行数并为随机"字段生成随机数现在这有效:

Im trying to count the number of rows in the table and generate random numbers for the field 'random' Now this works:

SELECT COUNT(*) FROM my_table;

这有效:

UPDATE my_table SET random = FLOOR(6500 * RAND()) + 1;

但这不起作用:

UPDATE my_table SET random = FLOOR((SELECT COUNT(*) ) * RAND()) + 1;

但这会将行数为 0 并加一，因此所有字段都具有数字 1 而不是唯一的随机数.

But this counts the rows as 0 and adds one so all fields have the number one instead of a unique random number.

任何我做错的想法都会最有帮助.

Any ideas what I'm doing wrong would be most helpful.

推荐答案

这个怎么样?

SELECT @cnt := count(*) FROM my_table; UPDATE my_table SET random = FLOOR(@cnt * RAND()) + 1;

演示:http://sqlfiddle.com/#!2/a896d/4

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