20 - 每月交易 I（高频 SQL 50 题基础版)

20 - 每月交易 I

--  考点：日期转换格式
--  date_format(trans_date,'%Y-%m')

select 
    date_format(trans_date,'%Y-%m') month,
    country,
    count(*) trans_count,
    sum(if(state='approved',1,0)) approved_count,
    sum(amount) trans_total_amount,
    sum(if(state="approved",amount,0)) approved_total_amount
from
    Transactions 
group by
    month,country;