Kluczowe polecenia
Pobiera kolumny z tabeli. SELECT column1, column2 FROM products; SELECT * zwraca wszystkie kolumny. Filtruje wiersze.
SELECT * FROM sales WHERE sale_date >= '2024-01-01'; Łączy dane z wielu tabel.
SELECT s.sale_date, s.qty, p.category FROM sales s JOIN products p ON p.sku_id = s.sku_id; Agreguje dane.
SELECT store_id, SUM(qty) AS total_qty FROM sales GROUP BY store_id HAVING SUM(qty) > 1000; Sortuje wynik.
SELECT sku_id, revenue FROM sales_summary ORDER BY revenue DESC;