Question

给定日期D，是否有办法找出每个用户的当前有效订阅或最近过期的订阅。

这是表结构

user_subscription(
    user_subscription_id PRIMARY KEY,
    user_id,
    subscription_start_date,
    subscription_end_date,
    user_subscription_count
)

示例数据：

1   1   01-jan-2011     31-jan-2011     1
2   1   01-mar-2011     01-apr-2011     2
3   1   03-jun-2011     05-dec-2011     3
4   2   05-jan-2011     11-jan-2011     1
5   2   01-jun-2011     01-nov-2011     2

示例结果：

D = 15-jan-2011将是用户1的第1行和用户2的第4行。

我正努力想办法在SQL中做到这一点。

目前，我为每个用户单独进行查询，但为数千名用户执行此操作的成本很高。

非常感谢任何帮助/想法！

谢谢！

Answer 1

您可以使用ROW_NUMBER：

DECLARE @d DATE = '20110115'

;WITH Cte AS(
    SELECT *,
        rn = ROW_NUMBER() OVER(PARTITION BY user_id ORDER BY subscription_start_date DESC)
    FROM user_subscription
    WHERE
        subscription_end_date <= @d 
)
SELECT
    user_subscription_id, user_id,subscription_start_date, subscription_end_date
FROM cte

Answer 2

在这里小提琴：http://sqlfiddle.com/#!3/95688

DECLARE @D AS DATE='15-jan-2011'
;WITH CTE 
as
(   SELECT * 
    FROM user_subscription 
    WHERE (@D BETWEEN subscription_start_date and subscription_end_date) OR subscription_end_date <= @D 
),
CTE1
AS
(
   SELECT ROW_NUMBER() OVER(PARTITION BY USER_ID ORDER BY subscription_end_date DESC) AS RN,*
   FROM CTE
)

SELECT * FROM CTE1 WHERE RN=1

Answer 3

假设每个用户的订阅按照user_subscription_count按时提升，并且只有一个订阅，请尝试：

select *
  from user_subscription s
 where user_subscription_count =
       (select max(x.user_subscription_count)
          from user_subscription x
         where x.user_id = s.user_id
           and x.subscription_start_date < @D)

用于查找当前活动日期范围或上次传递日期范围的SQL查询

3 个答案: