- Basic Concepts
- PostgreSQL JOIN statement combines two or more tables
- Tables are related by common columns like student ID
- Join conditions are required for all join types
- Join Types
- Cross join returns Cartesian product of two sets
- Inner join combines rows based on join conditions
- Natural join compares columns with same names implicitly
- Left join matches left table rows with right table
- Right join matches right table rows with left table
- Full join combines left and right join results
- Implementation
- Tables can be created using CREATE TABLE statements
- USING clause simplifies join conditions
- Join conditions can be explicit or implicit
- NULL values appear in unmatched rows