Aggregating data percentage wise based on date related criteria from a table

I have legacy tables which tracks flight and had to extract data. We have three tables named booking, airlines and flighttype. Note this is a dummy samples

booking :

id	customer	request_date	airline	flightType	price	currency
1	1	11-20-2020 10:23	1	1	120	Eur
2	1	11-21-2020 10:24	1	2	110	CHF
3	2	11-01-2020 11:25	2	2	120	Eur
4	1	15-01-2020 10:23	1	1	100	Eur
5	1	11-01-2020 11:23	1	2	60	Eur
6	1	12-01-2020 10:23	1	3	35	Eur

airline :

id	airline
1	French
2	Swiss

type :

id	flightType
1	domestic
2	international

Now the data we are trying to figure out is number of bookings consecutively within x days (let say if two days it would mean how many bookings were made in 2 days) for various parameters like

• airline
• flightType
• airline & flightype
• currency
• price total price

For example lets say I wish to see what is the percentage of customer who have made multiple bookings within x days across multiple airline I should be able to do so or if I want to see the total revenue of customers who have made multiple booking within x days or customers who have made multiple booking with different set of currencies with x days

I am trying to make self join to extract such data and then group it but I am always reaching a dead end

SELECT 
    t1.customer, t1.request_date, t1.airline, count(*)
    FROM booking t1 
    JOIN booking t2 
    ON t1.customer= t2.customer
    WHERE t2.request_date > t1.request_date and DATEDIFF(t2.request_date, t1.request_date) > 0 and DATEDIFF(t2.request_date, t1.request_date) <=2
    GROUP BY t1.customer, t1.request_date

The problem I am facing is the date has time and it gives me wrong results. And I am not sure what is the right way to get %share of customers who make booking in such way like % share of customers who book more than one flight / more than one type of flight within span of x days.

Sorry if the question is too vague or if this violates any rules. By the way I am using mysql 5.5

Answer

I want to see the total revenue of customers who have made multiple booking within x days or customers who have made multiple booking with different set of currencies with x days

You can answer questions like this using window functions. For the first question, this looks like:

select count(distinct customer)
from (select b.*,
             lag(request_date) over (partition by customer order by request_date) as prev_request_date
      from booking b
     ) b
where request_date <= prev_request_date + interval <n> day;