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
RussiaorChina.
Query 2
- Returns all rows where the country is either
JamaicaorNew Zealand.
Questo esercizio fa parte del corso
Improving Query Performance in SQL Server
Esercizio pratico interattivo
Prova a risolvere questo esercizio completando il codice di esempio.
-- Query 1
SELECT *
FROM Cities
WHERE CountryCode = ___ -- Country code
OR CountryCode = ___ -- Country code