mysql 统计日月年

SELECT DATE(order_date) AS order_day, COUNT(*) AS order_count
FROM orders
GROUP BY order_day
ORDER BY order_day;

SELECT YEAR(order_date) AS order_year, MONTH(order_date) AS order_month, COUNT(*) AS order_count
FROM orders
GROUP BY order_year, order_month
ORDER BY order_year, order_month;

SELECT YEAR(order_date) AS order_year, COUNT(*) AS order_count
FROM orders
GROUP BY order_year
ORDER BY order_year;

SELECT * FROM orders WHERE order_date IS NULL OR order_date = '';

UPDATE orders SET order_date = '2023-01-01' WHERE order_date IS NULL OR order_date = '';

CREATE INDEX idx_order_date ON orders(order_date);

SELECT DATE(order_date) AS order_day, COUNT(*) AS order_count
FROM orders
GROUP BY order_day
ORDER BY order_day
LIMIT 10 OFFSET 0;