PHP - cannot find correct regex -

PHP - cannot find correct regex -

i trying figure out regex match 012 wound't match 0. if string 1 character , character equals 0 should false should work values 012, 023, 01, 05, 120.

i tried doesn't want.

^(?=[^0])(?=[0-9]{1,3})$

any idea?

^(?!0$)\d+$

try this.see demo.

http://regex101.com/r/dz1vt6/27

regex