Advanced PostgreSQL Practice Session | Real SQL Interview Questions & Solutions
Thapa Technical
Jun 19, 2026
This session bridges the gap between basic SQL theory and complex enterprise requirements. It demonstrates how to combine multiple Joins, Aggregate functions, Grouping, and complex filtering via Having clauses into a single, high-level query to solve real business problems like identifying top-spending students.
Key insight: When building complex business queries, filtering before aggregation requires the 'WHERE' clause, while filtering on aggregate results (like a specific total spent amount) must be performed using the 'HAVING' clause after the 'GROUP BY' statement.
