mysql int field growing bigger than 11 digits

Question

I have a mysql database, and I am using it as a temprorarily store captcha values. It has a auto incremented id key, with int(11) field. What happens if this value gets bigger than 11 digits?

Answer 1

A typical INT uses 4 bytes, so it can store the numbers:
Signed: -2147483648 to 2147483647
Unsigned: 0 to 4294967295

A BIGINT uses 8 bytes, so it can store the numbers:
Signed: -9223372036854775808 to 9223372036854775808
Unsigned: 0 to 18446744073709551615

Answer 2

This number (11) has absolutely nothing to do with column range - [SIGNED] INTEGER defines a range (-2147483648 - 2147483647).

Number within parentheses is being used only when combined with ZEROFILL. Then it defines the "length" of displayed number, ie. value 275552 will be returned as string 00000275552.