SQL-консоль
SELECT · INSERT · UPDATE · DELETE — өзгерістер бірден базаға түседі
SQL кеңес
Кестелер
products — id, product_name, price, category
customers — id, name, city
orders — id, customer_id, product_id, quantity
movies — id, title, genre, year
viewers — id, name, phone
tickets — id, customer_id, movie_id, seat
Шарттар: = != > < >= <= like '%...%' and
Ереже: UPDATE және DELETE тек WHERE-пен. UPDATE-те бірнеше өріс болады: set a = 1, b = 'x'.
JOIN: select c.name, p.product_name, o.quantity from orders o join customers c on o.customer_id = c.id join products p on o.product_id = p.id;
Агрегат: count(*), sum(), avg(), min(), max() және group by.
SELECT
select * from products where price > 10000 order by price desc;
INSERT
insert into products
(product_name, price, category)
values ('Веб-камера', 25000, 'Аксессуар');
UPDATE
update products set price = 99000 where id = 4;
DELETE
delete from products where id = 6;
Байланыс: orders.customer_id → customers.id, tickets.movie_id → movies.id.