How to prevent negative number in Mysql

Question

Hello guys.. I have data which is starting from 0 in my database.

My php will add 1 or -1 to the data depending on the user's input. My problem is that if data is 0 and a user try to subtract 1. The data become 4294967295 which is the maximum value of INT data type. Are there anyways to make the data stays in 0 even when the user asks for -1? Thanks for the reply..

my sql command is like below

update board set score=score-1 where team='TeamA'
//this would generate 4294967295 if the score is 0.....

Answer 1

Yes..

UPDATE board SET score = score - 1 WHERE team = 'TeamA' AND score > 0

Answer 2

update board set score=score-1 
where team='TeamA'
and score > 0

Answer 3

Why not just add AND SCORE > 0

Answer 4

ALTER TABLE board MODIFY score UNSIGNED INT;

Answer 5

Did you set your column as unsigned?