如何在不执行操作的情况下将列的值设置为-1（减1）

Question

I have a MySQL table where I have an integer column that I want to use php to set to -1. But the problem is that anytime I do

mysqli_query($con, "UPDATE mytable SET mycolomn='-1' ") or die(mysqli_error($con));

It does not set it to minus one "-1", rather I sets it to 0. I need the number in that field to be changed to minus one "-1" without it been set to 0.

I have tried to change the column to Decimal but still the same problem.

Answer 1

Check your table to see what type of INT you have. An UNSIGNED INT cannot be negative.

Type          Storage         Min           Max
INT                 4 -2147483648    2147483647
INT UNSIGNED        4           0    4294967295