What is Cross Join?
Cross Join combines EVERY row from first table with EVERY row from second table.
Simple rule: 3 colors × 2 sizes = 6 combinations
How Cross Join Works
Basic Syntax
SELECT *
FROM table1
CROSS JOIN table2;Example: All Color-Size Combinations
SELECT colors.name, sizes.name
FROM colors
CROSS JOIN sizes;Result: 4 rows (2 colors × 2 sizes)
Warning!
Cross Join creates many rows fast!
- 10 × 10 = 100 rows
- 100 × 100 = 10,000 rows
- 1000 × 1000 = 1,000,000 rows!
When to Use
- Generate all product variants (color + size)
- Create date ranges
- Test data combinations
Try It Below
Practice with color-size combinations!
Congratulations!
You completed all JOIN types! 🎉