Can ORDER BY be used together with SELECT to control the presentation order of the rows returned by a query?

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
SQL does not guarantee row order unless ORDER BY is specified. This question verifies that ORDER BY is the standard mechanism to sort SELECT output in ascending or descending order by one or more expressions.



Given Data / Assumptions:

  • We are executing a SELECT statement.
  • We want a deterministic presentation order.
  • We can specify ASC or DESC per sort key.


Concept / Approach:
ORDER BY appends to SELECT to sort rows by column(s) or expressions. Without it, the DBMS may return rows in any order that satisfies the query plan. ORDER BY is independent of indexes, GROUP BY, or data types; it is a logical directive that the optimizer will implement, possibly via sorting or index scans.



Step-by-Step Solution:

Write the SELECT to produce the desired columns and filters.Add ORDER BY with one or more sort expressions.Choose ASC or DESC per expression.Test to confirm stable ordering across runs.


Verification / Alternative check:
Compare results with and without ORDER BY; only the ORDER BY version ensures deterministic order, which is critical for pagination and consistent reporting.



Why Other Options Are Wrong:

  • “Incorrect” ignores basic SQL behavior.
  • Indexes may improve performance but are not required.
  • GROUP BY is not a prerequisite.
  • ORDER BY works for any sortable data type, not just numbers.


Common Pitfalls:
Assuming “natural” order equals insertion order—this is unreliable. Always use ORDER BY for predictable presentation.



Final Answer:
Correct

More Questions from Introduction to SQL

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion