SUM and AVG calculations

Concepts: sqlSumAvg

SUM Functions Basic Example SUM with GROUP BY Each group's amounts are added together into a single total. North's three sales (150 + 175 + 190) become 515, while East's lone sale stays at 160. Now you can instantly see which region generates the most revenue and sells the most units. SUM with Expressions You can sum calculated values, not just raw columns. This is common for computing totals from unit prices and quantities. The expression price * quantity is calculated for each row, then those products are summed together. Grand vs Group Totals Handling Empty Data Database Execution AVG Functions AVG() Basic Example The average order value across all orders is $127.43. AVG with GROUP BY Each group's salaries are averaged independently. Engineering's three salaries produce a higher mean th