帮我写一些高级的sql 语句

当然可以，以下是一些高级 SQL 语句的示例：

1. 使用子查询进行过滤

SELECT *
FROM customers
WHERE customer_id IN (
  SELECT customer_id
  FROM orders
  WHERE order_date >= '2021-01-01'
);

2. 使用 GROUP BY 对结果进行聚合

SELECT category, COUNT(*) as count
FROM products
GROUP BY category
ORDER BY count DESC;

3. 使用 JOIN 连接多个表

SELECT customers.customer_name, orders.order_date, order_items.quantity
FROM customers
JOIN orders ON customers.customer_id = orders.customer_id
JOIN order_items ON orders.order_id = order_items.order_id
WHERE customers.country = 'USA';

4. 使用 UNION 合并多个查询结果

SELECT customer_name, email
FROM customers
WHERE country = 'USA'
UNION
SELECT customer_name, email
FROM customers
WHERE country = 'Canada';

5. 使用 WITH 子句创建临时表

WITH top_customers AS (
  SELECT customer_id, SUM(total) as total_spent
  FROM orders
  GROUP BY customer_id
  ORDER BY total_spent DESC
  LIMIT 10
)
SELECT customers.customer_name, top_customers.total_spent
FROM customers
JOIN top_customers ON customers.customer_id = top_customers.customer_id;

这些 SQL 语句涉及了子查询、聚合、连接、合并和临时表等高级技术，希望对你有所帮助。