MySQL Query: Get new customers in the month

Question

I have millions of records in a table with following columns:

id, item_id, customer_id, date

I want to find customer_id for a specific month which are inserted first time in the table in that month.

What is best and simple query for this.

Thanks

Answer 1

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

Answer 2

try something like:

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