分区 SQL

Question

我一直在尝试找出在给定时间段内某个帐户（人）被提供商 (provider_code) 查看 (appt_id) 的中位数。所附的 SQL 并未捕获所有 provider_code，我不明白为什么。期望的结果是所有 provider_code 都以中位数列出。

*我无法访问 MS SQL Server 2012 或更新版本 - 是的，我们落后于时代，是的，它确实让生活变得更加困难。

SELECT
   provider_code, office_location,
  CONVERT(INT, count(account)) AS Median

FROM
(
   SELECT
      office_location,provider_code,
   account,appt_date,dept_code,appt_status,appt_class,
      ROW_NUMBER( ) OVER (
         PARTITION BY office_location,provider_code
         ORDER BY account ASC) as RowAsc, 

      ROW_NUMBER( ) OVER (
         PARTITION BY office_location,provider_code
         ORDER BY account DESC) as RowDesc

   FROM appointments_view WITH(NOLOCK)


WHERE account IS NOT NULL AND appt_date BETWEEN '1/1/17' /*24 month prior*/ AND '1/1/19' 


 ) X


WHERE 
   RowAsc IN (RowDesc, RowDesc - 1, RowDesc + 1)


GROUP BY office_location,provider_code
ORDER BY office_location,provider_code

Answer 1

对于中位数，您可以使用 window 函数 PERCENTILE_CONT or PERCENTILE_DISC
(MS Sql 服务器 2012+)

示例片段：

declare @Appointments table (
 appt_id int primary key identity(4046100,1), 
 appt_date date not null default GetDate(), 
 account int not null, 
 provider_code varchar(10) not null, 
 office_location char(3) not null default 'REN', 
 appt_class char(3) not null 
 );

insert into @Appointments (appt_date, account, provider_code, appt_class) values
('2019-02-01',100001,'FOO1','IND'),('2019-02-01',100002,'FOO1','IND'),('2019-02-01',100002,'FOO1','PSY'),('2019-02-01',100002,'FOO1','IND'),
('2019-02-01',100002,'FOO1','IND'),('2019-02-01',100003,'FOO1','IND'),('2019-02-01',100003,'FOO1','IND'),('2019-02-01',100003,'FOO1','IND');

select provider_code, office_location, MAX(MedianContTotalAppointments) AS MedianApt
from
(
    select provider_code, office_location, account
    , count(appt_id) as TotalAppointments
    , PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY count(appt_id)) OVER (PARTITION BY provider_code, office_location) AS MedianContTotalAppointments
    -- , PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY count(*)) OVER (PARTITION BY provider_code, office_location) AS MedianDiscTotalAppointments
    from @Appointments
    where account IS NOT NULL 
      and appt_date BETWEEN cast('2017-02-01' as date) AND cast('2019-02-01' as date)
    group by provider_code, office_location, account
) q
group by provider_code, office_location
order by provider_code, office_location;

Returns:

provider_code   office_location     MedianApt
FOO1            REN                 3

在 2012 年之前的 MS Sql 服务器版本中，此示例代码段可能有效：

declare @Appointments table (
 appt_id int primary key identity(4046100,1), 
 appt_date date not null default GetDate(), 
 account int not null, 
 provider_code varchar(10) not null, 
 office_location char(3) not null default 'REN', 
 appt_class char(3) not null 
 );

insert into @Appointments (appt_date, account, provider_code, appt_class) values
 ('2019-02-01',100001,'FOO1','IND'),('2019-02-01',100002,'FOO1','IND'),('2019-02-01',100002,'FOO1','PSY'),('2019-02-01',100002,'FOO1','IND')
,('2019-02-01',100002,'FOO1','IND'),('2019-02-01',100003,'FOO1','IND'),('2019-02-01',100003,'FOO1','IND'),('2019-02-01',100003,'FOO1','IND')
--,('2019-02-01',100004,'FOO1','IND'),('2019-02-01',100004,'FOO1','IND')
;

select provider_code, office_location, AVG(TotalAppointments) AS MedianApt
from
(
    select provider_code, office_location, account
    , COUNT(appt_id) as TotalAppointments
    , ROW_NUMBER() OVER (PARTITION BY provider_code, office_location ORDER BY COUNT(appt_id) ASC) AS rn
    , COUNT(*) OVER (PARTITION BY provider_code, office_location) AS cnt
    from @Appointments
    where account IS NOT NULL 
      and appt_date BETWEEN cast('2017-02-01' as date) AND cast('2019-02-01' as date)
    group by provider_code, office_location, account
) q
where rn in (FLOOR((cnt+1)*0.5), CEILING((cnt+1)*0.5))
group by provider_code, office_location
order by provider_code, office_location;

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