Mysql generates random numbers with fixed digits

The project needs to dynamically generate random numbers with fixed digits, such as 8-bit and 5-bit.

The method we saw earlier is as follows:

ROUND (RAND (), 5) * 100000)

This is not accurate, and there is a probability that four digits will occur. The Rand () function is 0 ~ 1 (infinitely close) Random Function

If a random number is 0.05321

In this way, the conversion is 5321, with only four digits.

If you can wrap it with a function, when you find that the number of digits is incorrect after the value is obtained, it is perfect to fill in the bits.

The following is a function I modified, but the disadvantage is that the number of digits of the generated function cannot exceed 20. Of course, you can change it.

DELIMITER $

USE 'prvecard '$

Drop function if exists 'getrand' $

Create definer = 'pecard '@' % 'FUNCTION 'getrand' (counts INTEGER) returns varchar (20) CHARSET utf8
BEGIN
DECLARE sTemp VARCHAR (20 );
DECLARE sTempCounts INTEGER;
SET sTemp = CONCAT (ROUND (RAND (), counts) * (POW (10, counts ))),);

IF (CHAR_LENGTH (sTemp) <counts) THEN

SET sTempCounts = counts-CHAR_LENGTH (sTemp );
SET sTemp = CONCAT (sTemp, RIGHT (CONCAT (POW (10, sTempCounts),), sTempCounts ));
End if;

RETURN sTemp;
END $

DELIMITER;