Find users whose age is NOT 25 or 30.
Problem Statement
Examples
Input: users table: +----+---------+-----+ | id | name | age | +----+---------+-----+ | 1 | Alice | 30 | | 2 | Bob | 25 | | 3 | Charlie | 35 | | 4 | Dana | 40 | +----+---------+-----+
Output: +----+---------+-----+ | id | name | age | +----+---------+-----+ | 3 | Charlie | 35 | | 4 | Dana | 40 | +----+---------+-----+
Explanation: Only records matching the specified criteria are returned in the final result.
Complexity
Time Complexity: -
Space Complexity: -
Hints
Editorial & Approach
Problem Overview & Intuition
To solve "Filter with NOT IN", we query the relational database engine using declarative SQL. The goal is to find users whose age is not 25 or 30. 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 WHERE filtering to isolate the requested data.
- Format & Order: Ensure columns match the expected project schema in order.
Optimal Implementation (SQL)
SELECT * FROM users WHERE age NOT IN (25, 30);
Complexity Analysis
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.