Clustered index

Clustered indexes can be added to tables to speed up search operations in queries. You have two copies of the Cities table from the Earthquakes database: one copy has a clustered index on the CountryCode column. The other is not indexed.

You have a query on each table with a different filter condition:

Query 1

Returns all rows where the country is either Russia or China.

Query 2

Returns all rows where the country is either Jamaica or New Zealand.

This exercise is part of the course

Improving Query Performance in SQL Server

View Course

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

-- Query 1
SELECT *
FROM Cities
WHERE CountryCode = ___ -- Country code
		OR CountryCode = ___ -- Country code

Edit and Run Code