如何找出特定月份最畅销的书籍类别

Question

我正在尝试计算特定月份（例如一月份）销售量最大（书籍）的类别。我的payment_date列为日期时间格式。它说我的SQL语法有以下查询错误

SELECT category_id, SUM(payment_amount) AS Total FROM Payments GROUP BY category_id WHERE MONTH(payment_date) = 01 ORDER BY SUM(payment_amount) DESC LIMIT 1

Answer 1

该语句的GROUP BY部分需要放在WHERE子句之后，因此您的查询应该是：

SELECT category_id, SUM(payment_amount) AS Total FROM Payments WHERE MONTH(payment_date) = 1 GROUP BY category_id ORDER BY SUM(payment_amount) DESC LIMIT 1