Mysql question: Why set a length for Int?

[mrthumbs]

Unlike Varchar setting a length for Int doesnt change anything.

Int(1) and Int(999) both store 2 billion numbers.. so whats the reason
for Mysql saving Length data?

[studiocritic]

Originally Posted by mrthumbs

Unlike Varchar setting a length for Int doesnt change anything.

Int(1) and Int(999) both store 2 billion numbers.. so whats the reason
for Mysql saving Length data?

INT actually holds 4 billion - http://dev.mysql.com/doc/mysql/en/numeric-types.html..

The reason is just for display when you SELECT it, the number 4 in INT(4) is how wide the column will be.