Finding the value.

Hello.I'm trying to inject to get free silks and when I tamper it says "Invalid value,please try again"
1' UPDATE SK_Silk SET silk_own=9975 WHERE JID = (SELECT JID FROM TB_User WHERE StrUserID ='myusername') --

And you assume that every website is vulnerable to sql injections?

first, not coding related
second, we dont allow direct hacks(game hacks like Unlimited HP or something like that is allowed since it doesn't goes around money)
#closed