CONTAINS() — Returns true or false depending if a point falls within the specified polygon.
CONTAINS( polygon, point )
The CONTAINS() function determines if a given point falls within the specified GEOGRAPHY polygon. If so, the function returns a boolean value of true. If not, it returns false.
The following example uses the CONTAINS function to see if a specific user is with the boundaries of a city or not by evaluating if the user.location GEOGRAPHY_POINT column value falls within the polygon defined by the city.boundary GEOGRAPHY column.
SELECT user.name, user.id, city.name FROM user, city WHERE user.id = ? AND CONTAINS(city.boundary,user.location);