SELECT * FROM data_order WHERE id IN (SELECT order_id FROM data_order_detail WHERE goods_id IN (SELECT id FROM data_goods WHERE third_category_id = 51);
SELECT cust_name,cust_state,(SELECT COUNT(*) FROM orders WHERE orders.cust_id = customers.cust_id) AS orders FROM customers ORDER BY cust_name;
SELECT cust_name,cust_state FROM orders,customers WHERE orders.cust_id = customers.cust_id ORDER BY cust_name;
SELECT cust_name,cust_state FROM orders INNER JOIN customers ON orders.cust_id = customers.cust_id;
SELECT prod_name,vend_name,prod_price,quantityFROM orderitems,products,vendors WHERE products.vend_id = vendors.vend_idAND orderitems.prod_id = products.prod_idAND order_num = 20005;
并查询:union
复合查询:compoundquery