如何编写SQL查询来找出一年中每月至少购买两次的客户

Question

I have a table with columns order_id, customer_id, order_date and Amount.

How to find the customers who have ordered at least 2 times each month of the year in SQL (from Jan to Dec)?

Answer 1

I think you are looking for something like this

select
    order_date_year,
    customer_id
from 
(
    select  
        year(order_date) as order_date_year,
        month(order_date) as order_date_month,
        customer_id,
        count(*) as number_of_orders
    from
        tableName
    group by
        year(order_date),
        month(order_date),
        customer_id
    having
        count(*) >= 2
) as t
group by
    order_date_year,
    customer_id
having
    count(*) = 12