Okay, so my monsters table has a column called "droparray" for example: 7,2,5
7,2,5 are the id's of the items they could POSSIBLE get when they kill the monster 
[Intuitive eh?]
I need a way to just select a random number from those 3 numbers (or any amount) AND a way to let's say if 7 was a unique item, have it a less % chance.
Any ideas?