MySQL 使用 GROUP BY 按日期排序

MySQL是一种广泛使用的关系型数据库管理系统，它提供了强大的数据存储和查询功能。在MySQL中，我们经常需要对数据进行分组并按照特定的字段进行排序。本文将介绍如何使用GROUP BY语句按日期排序数据，并提供相应的案例代码。

sql
SELECT DATE_FORMAT(date_column, '%Y-%m-%d') AS date, COUNT(*) AS count
FROM table_name
GROUP BY date
ORDER BY date;

sql
CREATE TABLE orders (
  order_id INT PRIMARY KEY,
  order_date DATE,
  amount DECIMAL(10, 2)
);
INSERT INTO orders (order_id, order_date, amount) VALUES
(1, '2022-01-01', 100.00),
(2, '2022-01-01', 200.00),
(3, '2022-01-02', 150.00),
(4, '2022-01-02', 250.00),
(5, '2022-01-03', 300.00);
SELECT DATE_FORMAT(order_date, '%Y-%m-%d') AS date, COUNT(*) AS count
FROM orders
GROUP BY date
ORDER BY date;

+------------+-------+
| date       | count |
+------------+-------+
| 2022-01-01 | 2     |
| 2022-01-02 | 2     |
| 2022-01-03 | 1     |
+------------+-------+