Sort the `users` table by age in descending order.

Problem Statement

<p>Sort the <code>users</code> table by age in descending order.</p>

Examples

Input: users table: +----+---------+-----+ | id | name | age | +----+---------+-----+ | 1 | Alice | 30 | | 2 | Bob | 25 | | 3 | Charlie | 35 | +----+---------+-----+

Output: +----+---------+-----+ | id | name | age | +----+---------+-----+ | 3 | Charlie | 35 | | 1 | Alice | 30 | | 2 | Bob | 25 | +----+---------+-----+

Explanation: The query retrieves the requested records satisfying all problem requirements.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Determine the sort order (ASC for ascending, DESC for descending) and whether only top records are required. 💡 Hint 2: Specify ORDER BY <column> [ASC|DESC] and append LIMIT <n> to cap the result set. 💡 Hint 3: Assemble: SELECT <cols> FROM <table> ORDER BY <col> [DESC] LIMIT <n>;

Editorial & Approach

Problem Overview & Intuition

To solve "Sorting Results (ORDER BY DESC)", we query the relational database engine using declarative SQL. The goal is to sort the `users` table by age in descending order. By formulating an optimal execution plan with appropriate projection and filtering, the database engine executes the query with minimal overhead.

Step-by-Step Approach

Analyze Schema: Identify the target tables, necessary foreign keys, and expected output columns.
Construct Filtering & Logic: Apply row projections to isolate the requested data.
Format & Order: Sort the resulting records according to specified order criteria.

Optimal Implementation (SQL)

SELECT * FROM users ORDER BY age DESC;

Complexity Analysis

Time Complexity O(N log N) for sorting or partitioning rows.

Space Complexity O(N) for intermediate group hash tables or window buffers.

Key Considerations & Edge Cases

Empty Tables: The query executes safely returning zero rows without syntax error.
NULL Values: Columns containing NULL values are properly handled by standard ANSI SQL semantics.
Case Sensitivity: String comparisons and keywords adhere to PostgreSQL/standard SQL rules.

Sorting Results (ORDER BY DESC)

Easy

Sort the users table by age in descending order.

Example Scenarios

1Example 1

Input:

users table

id	name	age
1	Alice	30
2	Bob	25
3	Charlie	35

Output:

id	name	age
3	Charlie	35
1	Alice	30
2	Bob	25

Explanation:

The query retrieves the requested records satisfying all problem requirements.

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