[SQL] How do you count distinct records?

[Energycore]

So I've been dabbling in code, and so far I've had a lot of fun with SQL. I do have an interesting question though.

 

Suppose you have the following table named countries:

 

country		year	population
US		1998	12345
US		1999	23456
US 		2000	34567
CANADA		1998	54321
CANADA 		1999	65432
CANADA		2000	76543
MEXICO		1998	42069
MEXICO		1999	69420
MEXICO		2000	96024

How can you write a query that returns the number of distinct countries from the country column? Because I can query a table of each distinct country with this:

SELECT DISTINCT country
FROM countries;

-- Returns country US, country CANADA, country MEXICO

 

And that will return each distinct country to be counted manually. However, if I'm working with a big data set (and that's the point of using SQL), I might have thousands of distinct entries to the point that it's too many to count, or even for the computer to handle. Any ideas? I'm open to any new documentation.

[Bacon soup]

https://www.w3schools.com/SQl/sql_count_avg_sum.asp

select count(country) from table_name

[elpiop]

SELECT COUNT (DISTINCT country)

FROM countries;

[Energycore]

Just now, Bacon soup said:

https://www.w3schools.com/SQl/sql_count_avg_sum.asp

select count(country) from table_name

Right, that's how you would do it. Problem is:

SELECT COUNT(country)
FROM countries;

-- Returns 9 (counts each instance of US, CANADA and MEXICO as its own)

And if you try this

SELECT COUNT(country)
FROM COUNTRIES
GROUP BY country;

-- Returns:

-- 3
-- 3
-- 3

-- Which is the number of times each country shows up in a record.

 

[Energycore]

3 minutes ago, elpiop said:

SELECT COUNT (DISTINCT country)

FROM countries;

That worked! So it was all about correctly using parentheses. Thanks!

 

Edit: don't forget to use code tags for clarity in the future