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.
Este exercício faz parte do curso
Improving Query Performance in SQL Server
Exercício interativo prático
Experimente este exercício completando este código de exemplo.
-- Query 1
SELECT *
FROM Cities
WHERE CountryCode = ___ -- Country code
OR CountryCode = ___ -- Country code