Count and Sum

-- Drill 08 — COUNT و SUM و متوسط مقتطع — SQLite 3.x+
CREATE TABLE orders (
  id INTEGER PRIMARY KEY,
  total_halalas INTEGER NOT NULL
);

INSERT INTO orders VALUES
  (1, 5000),
  (2, 7500),
  (3, 2500);

SELECT
  COUNT(*) AS order_count,
  SUM(total_halalas) AS total_halalas,
  SUM(total_halalas) / COUNT(*) AS avg_halalas_truncated
FROM orders;