Mysql - why use unsigned columns?

Originally Posted by Antivirus

I have been looking at many hacks, and notice that some tables have their columns unsigned, and others dont. I know that when a column is unsigned, it starts counting at 0, as opposed to negatives... but is that simply all that should determine assigning a column as unsigned??? the fact that there is simply no need for negative intergers in my scripts?

???

UNSIGNED is normally used with AUTO_INCREMENT, (which is used to create a sequence of unique identifiers), because the values of AUTO_INCREMENT are always postive integers.