SQL如何按日期和多个条件聚合

Question

I have this table:

id	ammount	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	ammount_sum_jan	n_transaction_jan	n_customer_jan	ammount_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.

• AMMOUNT: sum of ammount 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 ammount else 0 end) as ammount_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 ammount else 0 end) as ammount_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 dfix dates look like this. An aggregation of the methid 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 `ammount` ELSe 0 END) ammount_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 `ammount` ELSe 0 END) ammount_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 ake that dynamic