When invoked with an integer argument, RAND( ) uses that value to seed the random number generator. Each time you seed the generator with a given value, RAND( ) will produce the same sequence of random numbers. Following example will demonstrate it −
Example
mysql> Select RAND(1), RAND(1), Rand(1); +---------------------+---------------------+---------------------+ | RAND(1) | RAND(1) | Rand(1) | +---------------------+---------------------+---------------------+ | 0.40540353712197724 | 0.40540353712197724 | 0.40540353712197724 | +---------------------+---------------------+---------------------+ 1 row in set (0.00 sec)