SQL how to aggregate by date and multiple criteria - mysql

Question

I have this table:
id
amount
method
date
01
10
A
2022-01-24 12:27:14.440
02
80
A
2022-01-24 12:27:14.440
01
20
D
2022-02-24 12:27:14.440
01
10
D
2022-02-24 12:27:14.440
02
20
D
2022-02-24 12:27:14.440
03
30
D
2022-02-24 12:27:14.440
and I want this:
method
amount_sum_jan
n_transaction_jan
n_customer_jan
amount_sum_feb
n_transaction_feb
n_customer_feb
A
10
2
2
0
0
0
D
0
0
0
80
4
3
This is a table with 7 column and rows equal to the number of methods.
AMOUNT: sum of amount in one month of one method
N_TRANSACTIONS: number of transaction in one month with one method
N_CUSTOMER: number of customers (id) who used that method in one month
Can I get it with just one query?

Answer 1

You want to aggregate your data by method and have separate columns for January data and February data. You get this with conditional aggregation (CASE expression inside the aggregate function),
select
method,
sum(case when month(date) = 1 then amount else 0 end) as amount_sum_jan,
count(case when month(date) = 1 then 1 end) as n_transaction_jan,
count(distinct case when month(date) = 1 then id end) as n_customer_jan,
sum(case when month(date) = 2 then amount else 0 end) as amount_sum_feb,
count(case when month(date) = 2 then 1 end) as n_transaction_feb,
count(distinct case when month(date) = 2 then id end) as n_customer_feb
from mytable
group by method
order by method;

Answer 2

It is called pivot, and would for fix dates look like this.
An aggregation of the method for the year and month, and you can COUNT or SUM your number
select
`method`,
SUM(CASE WHEN EXTRACT( YEAR_MONTH FROM `date` ) = '202201' then `amount` ELSE 0 END) amount_sum_jan,
SUM(CASE WHEN EXTRACT( YEAR_MONTH FROM `date` ) = '202201' then 1 ELSE 0 END) n_transaction_jan,
COUNT(DISTINCT CASE WHEN EXTRACT( YEAR_MONTH FROM `date` ) = '202201' then `d` ELSE 0 END) n_customer_jan,
SUM(CASE WHEN EXTRACT( YEAR_MONTH FROM `date` ) = '202202' then `amount` ELSe 0 END) amount_sum_feb,
SUM(CASE WHEN EXTRACT( YEAR_MONTH FROM `date` ) = '202202' then 1 ELSe 0 END) n_transaction_feb,
COUNT(DISTINCT CASE WHEN EXTRACT( YEAR_MONTH FROM `date` ) = '202202' then `d` ELSe 0 END) n_customer_feb
from tab1
GROUP BY `method`
http://www.sqlfiddle.com/#!9/31d8ef/10
much more interesting would be to make that dynamic