In MySQL, UUID() function returns Universal Unique Identifier that generates 36 characters long value which is 5 part hexadecimal numbers. If you want to generate random password, you can make use of this function which generate random number.
Returns the string 85aeb064-8f73-11e5-85ef-02fcc4101968 (Note that this is random, when you execute you will get different value). As the total length is 36, you can make use of the result to get a random password with any length.