hello guys.. i have an app.. usually in the login page we put the hi' or 1=1-- in the username field rite? but how if anything that being put in the username will be converted into integer??

when i put hi' or 1=1--, the server will show Error:for input string....
putting the tautology in the password field may be not suitable because lets say i put the id = 3, when i bypassed the login the id will be different.. it is very weird..what happen actually?

anyone has the idea how to bypass that? tq :)