restricting user just to get aggregated information Using mysql, how to restrict a user just to get the aggregated information (eg. sums, averages, count) of the table and only if the result of the number of record is greater than the threshold?

For example, if the threshold is 2, the following query should not be responded if only one supplier is living in London. 

select count(*) from s where city = "london"


But this should not be responded.

select salary from s where city = "london" 


Because if user knows in advance that there is only one who live in London, he can know his salary. I want to prevent that.
Plan A:  Use GRANT to not let that user see salary.

Plan B:  Provide Summary Tables (with counts, totals, etc) of stuff that you are willing to let them see, then restrict (via GRANT) their privileges on a table basis.  (Or put the Summary Tables in a different database.)