Skills101
← All practice quizzes

Quiz: Indexing

5 questionsNo time limitPass: 60%+10 XP on first pass

Why some queries take seconds and others milliseconds. How a B-tree index works, clustered vs non-clustered, composite indexes, and when an index helps or hurts.

Log in to take the quiz

Free account · see your score, answers and explanations, earn XP

  1. Question 1

    Without a usable index, how does the database find matching rows?

  2. Question 2

    How many clustered indexes can a table have?

  3. Question 3

    An index exists on (city, created). Which query can use it best?

  4. Question 4

    What is a downside of adding many indexes?

  5. Question 5

    Which condition usually PREVENTS using an index on created?