MySQL查询：在这个月获得新客户

Question

我在表中有数百万条记录，其中包含以下列：

id, item_id, customer_id, date

我想查找特定月份的customer_id ，该月份会在该月的表格中首次插入。

什么是最好和最简单的查询。

谢谢

Answer 1

select customer_id , min(date) as min_date
from theTable
group by customer_id 
having min_date>=<the desired date>

Answer 2

尝试类似的东西：

SELECT
date_format(date,"%M") month,group_concat(customer_id ORDER BY customer_id) customer_ids
FROM
<table_name>
GROUP BY month;

Answer 3

这样的事情可能是：

select distinct(id) from customer
where month(date)='Your_month'
order by date