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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.

Cet exercice fait partie du cours

Improving Query Performance in SQL Server

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Exercice interactif pratique

Essayez cet exercice en complétant cet exemple de code.

-- Query 1
SELECT *
FROM Cities
WHERE CountryCode = ___ -- Country code
		OR CountryCode = ___ -- Country code
Modifier et exécuter le code