When a WHERE clause is processed, the operators are evaluated in the following order of precedence:
Parentheses have the highest precedence.
The AND operator has the next level of precedence.
The OR operator has the lowest level of precedence.
What does this mean? Well, look at the WHERE clause in Listing 6.9. The clause reads WHERE FirstName='Ben' AND LastName='Forta' OR FirstName='Rick' AND LastName='Richards'. AND is evaluated before OR so this statement looks for Ben Forta and Rick Richards, which is what we wanted.
But what would be returned by a WHERE clause of WHERE FirstName='Rick' OR FirstName='Ben' AND LastName= 'Forta'? Does that statement mean anyone whose first name is either Rick or Ben, and whose last name ...