How to get the number of distinct records in a SQL Server 2008 database?

Question

I have a table with users. Each user has a country row filled in (no user without a country).

How can i get the number of countries that has a user?

select distinct Country_CountryId 
from users

This returns a list with all different countries (their id from the country table). But how can I sum them into an int without getting all entries back to my MVC controller and then count them there.

I tried

select distinct count(Country_CountryId) 
from users

But that does not return a correct answer.

Example: table has 4 users.

• User 1: UK
• User 2: UK
• User 3: US
• User 4: Spain

This should result in a count of 3 distinct countries

Answer 1

Try this:

select
    count( distinct Country_Country_Id ) 
from users

The COUNT(DISTINCT column_name) function returns the number of distinct values of the specified column