Skip to main content
Advanced query features for complex data retrieval.

Common Table Expressions (CTE)

CTEs create temporary named result sets for use in queries.

Use Cases

CTEs are useful for:
  • Breaking complex queries into readable parts
  • Reusing the same subquery multiple times
  • Recursive queries

Subqueries

Filter using results from another query.

Example: Users with Orders

EXISTS

Check if a subquery returns any results.

Set Operations

Combine results from multiple queries.

UNION

Combine results, removing duplicates.

UNION ALL

Combine results, keeping duplicates.

INTERSECT

Return only rows that appear in both queries.

EXCEPT

Return rows from first query that don’t appear in second.

CASE Expressions

Conditional logic within queries. CASE must be used within GET expressions.

Multiple Conditions

CASE in WHERE

Database Support

Complete Examples

Active Premium Users with Order Stats

Users Without Recent Orders

Categorized Products

Next Steps

Window Functions

ROW NUMBER, RANK, LAG, LEAD

Joins

Combine multiple tables