摘要：
1. 两个日期相减 date_diff datediff('2019-07-27',activity_date) between 0 and 29 2. 日期与数字相减或者相加 1. mysql 如下语法 where activity_date between date_add("2019-07-2 阅读全文
摘要：
最终结果 # Write your MySQL query statement below select distinct b.item_category as Category, ifnull(sum(case when dayofweek(a.order_date) = 2 then a.qua 阅读全文