Question

I already provide sql fiddle with schema and sample data.

http://sqlfiddle.com/#!2/e9d22/7/0

If I would like to know how many province and how many cities in Thailand.

Country Name | No. Provinces | No. Cities
  Thailand   |   77          |  1234

I guess that it need to use multiple COUNT(*) but I dont know how to use it.

Anybody know please suggest solution?

Answer 1

You need to use GROUP BY and COUNT:

SELECT c.name, count(distinct p.id) provincecoutn, count(distinct city.id) citycount
FROM country c
  LEFT JOIN province p on c.id = p.country_id
  LEFT JOIN City on p.id = city.province_id
GROUP BY c.name

Good luck.