How to check value in IF statement..

[C# Programming]

Hi guyzz.. i have a doubt may be i have a query in C# coding and the query returns a string... Now i need to perform a check using if statement, my check is that if the query returns any string value then grant permission else access denied... Now my doubt is how do i specify "return any string value" in the if condition... plz advice...



If(query == ?????)
{
permission granted
}