Câu 24: 70-762: Developing SQL Databases

Database users report that SELECT statements take a long time to return results. You run the following Transact-SQL statement: You need to create one nonclustered covering index that contains all of the columns in the above table. You must minimize index key size. Which Transact-SQL statement should you run?

1. A. CREATE NONCLUSTERED INDEX IX_User ON Users (CountryCode, UserName);
2. B. CREATE NONCLUSTERED INDEX IX_User ON Users (CountryCode, UserStatus) INCLUDE (UserName);
3. C. CREATE NONCLUSTERED INDEX IX_User ON Users (CountryCode, UserStatus, UserName);
4. D. CREATE NONCLUSTERED INDEX IX_User ON Users (UserStatus, CountryCode) INCLUDE (UserName); — đáp án hiện tại