Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
An e-commerce company uses Azure SQL Database for order processing. The Orders table has columns: OrderID (unique, clustered index), CustomerID, OrderDate, Status, TotalAmount. A common query filters on CustomerID and OrderDate, and sorts by OrderDate descending. The query also returns TotalAmount. Which indexing strategy will produce the best query performance?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Create a nonclustered index on (CustomerID, OrderDate DESC) INCLUDE (TotalAmount)
This composite index supports the exact filter (CustomerID and OrderDate), the sort order (OrderDate DESC is included in the key), and the included TotalAmount column eliminates key lookups, making it a covering index for the query.
B
Distractor review
Create a nonclustered index on (OrderDate) INCLUDE (CustomerID, TotalAmount)
This index puts OrderDate first, but the query filters on CustomerID first; filtering on CustomerID would require scanning many date ranges for each CustomerID, which is less efficient than having CustomerID as the leading key.
C
Distractor review
Create a nonclustered index on (OrderDate DESC) INCLUDE (CustomerID, TotalAmount)
Similar to the previous option, the leading key is OrderDate, not CustomerID, making it suboptimal for queries that filter on CustomerID first.
D
Distractor review
Create a nonclustered index on (CustomerID) INCLUDE (OrderDate, TotalAmount)
This index has CustomerID as the leading key, but OrderDate is only included, not a key column. The query also sorts by OrderDate, which the index cannot provide efficiently because OrderDate is not part of the key. The sort would require a separate sort operation.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Related practice questions
Related DP-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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FAQ
Questions learners often ask
What does this DP-900 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Create a nonclustered index on (CustomerID, OrderDate DESC) INCLUDE (TotalAmount) — For queries that filter on multiple columns and include a sort, a covering nonclustered index on the filter columns with included columns for the returned data can avoid key lookups. A composite index on (CustomerID, OrderDate DESC) with TotalAmount as an included column matches the filter and sort, and covers the query, so all needed data is in the index leaf level.
What should I do if I get this DP-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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