包含in group by子句或partition by的case語句

Question

Customer   Decision      req_date       salary
   A       Approved     2017-06-13       1000
   A       Approved     2017-06-13       1000
   A       Pending      2017-06-13       500
   B       Pending      2017-10-23       800     
   B       final_stage  2017-10-20       400
   B       final_stage  2017-03-19       400

對於給定的客戶ID，

情況1：如果該決定被批准，則保留該客戶的所有批准記錄，並刪除其他記錄。

情況2：如果客戶沒有任何批准的決定，則根據最新的“ req_date”保留特定客戶的記錄，並在最近的“ req_date”的5天內保留記錄，並根據最低薪水選擇記錄

Customer   Decision      req_date       salary  
   A       Approved     2017-06-13       1000
   A       Approved     2017-05-13       1000
   B       final_stage  2017-10-20       400

Answer 1

行必須分三個步驟進行過濾。 我將使用cte來計算聚合，並為已批准和未批准的客戶使用兩個查詢的並集：

with cte as (
    select 
        customer, 
        bool_or(decision = 'Approved') as approved, 
        max(req_date) as last_date
    from my_table
    group by 1
)
select customer, decision, req_date, salary
from my_table
join cte using(customer)
where approved and decision = 'Approved'
union all (
    select distinct on(customer) customer, decision, req_date, salary
    from my_table
    join cte using(customer)
    where not approved 
    and req_date between last_date- '5day'::interval and last_date
    order by customer, salary
    )

DbFiddle。