SQL

Question 1

What statement would you use to return the “Country” value from all the records of the “Customers” table?

Table Customer

Answer 1

SELECT Country FROM Customers;

Question 2

What statement would you use to return the number of different countries?

Table Customer

Answer 2

SELECT Count(*) AS DistinctCountries
FROM (SELECT DISTINCT Country FROM Customers);

Count Distinct

Question 3

What is the Count Distinct Format

Answer 3

COUNT(DISTINCT column_name)

• DISTINCT is a keyword in a function
• COUNT is a function

Question 4

Which SQL statements would return a list of all unique countries from a table named Customers?

Answer 4

SELECT DISTINCT Country

FROM Customers;

Question 5

What would be the result of omitting the DISTINCT keyword in a statement like SELECT DISTINCT Country FROM Customers;?

Answer 5

It would return all values, including duplicates, in the Country column