MySQL-分类和计数项目

Question

My table has three columns 'name', 'city' and 'country'. Now I want to make a list with only those countries, which has at least 3 times the SAME city.

 name        city        country
 ----        ----        -------
 Smith       Boston      USA
 Wayne       St. Louis   USA
 Miller      Houston     USA
 Joseph      Houston     USA
 Obama       Washington  USA
 Jones       Houston     USA

 Sarkozy     Paris       France
 Merle       Paris       France
 Gabin       Marseille   France
 Delon       Avignon     France
 Deneuve     Avignon     France

 Trappatoni  Rome        Italy
 Linguini    Milano      Italy
 Mastroianni Rome        Italy

 Meier       Hamburg     Germany
 Müller      Munich      Germany
 Schmidt     Hamburg     Germany
 Böttcher    Hamburg     Germany
 Kunau       Hannover    Germany
 Wilhelm     Munich      Germany
 -------------------------------

                         USA
 Result:             
                         Germany

I tried it with distinct, count, group by etc. But without results.

Answer 1

Group by country and city then take only those having at least 3 entries each.

select distinct country
from your_table
group by country, city
having count(*) >= 3