SQL Server挑战性问题-寻找第一位买家、第二位/第三位买家、第四位或更多买家

节日快乐，各位

我被指派编写一个SQL查询，以显示在特定数据范围和位置购买特定产品的买家数量。 我需要找到以下内容：

第一次买主。 第二次/第三次买家。 第四次或更多次买家。 我第一次通过下面的查询找到了买家 ; 但无法找到第二/第三位买家、第四位或更多买家。有人能帮忙吗

DECLARE @from_dt        datetime
DECLARE @Day_End_dt     datetime

SET @from_dt =     '10/01/2010'
SET @Day_End_dt =  '12/29/2010'


select count(B.buyer_id) as California_1st_time_buyer
from
--LIST OF ALL BUYERS AND FIRST PURCHASED DATE THRU END OF DATE RANGE (10/1/98 - 12/28/10)
(select distinct buyer_id, min(purchased_date_time) as First_timer
from product_details
where purchased_date <@Day_End_dt
group by buyer_id
)A,
--LIST OF CALIFORNIA BUYERS AND FIRST PURCHASED DATE IN DATE RANGE (12/1/10 - 12/28/10)
(select distinct buyer_id, min(purchased_date_time) as First_timer_ca_in_date_range
from product_details
where purchased_date >=@from_d
and purchased_date <@Day_End_dt
and location = 'CA'
group by buyer_id
)B
where A.buyer_id = B.buyer_id
and A.First_timer = B.First_timer_ca_in_date_range



Input sample:
purchased_date_time     purchased_date      buyer_id
12/7/2010 12:30:00 PM       12/7/2010       5627242
--------------------------------------------------------------------
12/9/2010 4:30:00 PM         12/9/2010       9231374
12/19/2010 11:30:00 AM     12/19/2010      9231374
--------------------------------------------------------------------
12/9/2010 12:10:00 AM       12/9/2010       8061088
12/15/2010 5:00:00 PM       12/15/2010      8061088
12/21/2010 6:00:00 PM       12/21/2010      8061088
--------------------------------------------------------------------
12/1/2010 12:30:00 PM       12/1/2010       2288101
12/12/2010 6:30:00 PM       12/12/2010      2288101
12/27/2010 7:30:00 PM       12/27/2010      2288101
12/28/2010 6:30:00 PM       12/28/2010      2288101
--------------------------------------------------------------------
12/9/2010 10:45:00 AM       12/9/2010       2510454
12/16/2010 9:45:00 PM       12/16/2010      2510454
12/19/2010 4:19:00 AM       12/19/2010      2510454
12/22/2010 7:05:00 AM       12/22/2010      2510454
12/29/2010 2:30:00 AM       12/29/2010      2510454
--------------------------------------------------------------------
Output sample:
1st buyers =5 --count buyer_id who purchased the product first time ever in date range (12/1/10 - 12/28/10)

2nd/3rd buyers =7 --count buyer_id who purchased the product 2nd/3rd time in date range (12/1/10 - 12/28/10)

4th or more buyers =3  --count buyer_id who purchased the product 4th time or more in date range (12/1/10 - 12/28/10)

---

请注意，这些买家仅来自上述日期范围。假设一位买家在2010年12月1日之前购买了三次，并在2010年12月1日再次购买，他将被视为第四次购买。

我不完全理解你想做什么。如果您可以使用表结构、两个示例行和预期的输出来更新问题，这将有所帮助

无论如何，这里有一个尝试：

下面的查询应该会为您提供购买次数不超过四次的买家列表。现在还不清楚您是否只是想计算购买数量，或者您是否也需要实际购买日期，因此我为前4次购买添加了日期。如果买方仅进行了1次采购，则该行将在采购2/3/4列中显示NULL

如果要包括一系列日期或按位置筛选，则这些条件将进入内部选择

select buyer_id
      ,count(*) as purchases
      ,max(case when purchase_no = 1 then purchased_date end) as purchase_1
      ,max(case when purchase_no = 2 then purchased_date end) as purchase_2
      ,max(case when purchase_no = 3 then purchased_date end) as purchase_3
      ,max(case when purchase_no = 4 then purchased_date end) as purchase_4
  from (select buyer_id
              ,purchased_date
              ,row_number() over(partition by buyer_id
                                     order by purchased_date) as purchase_no
          from product_details
       )
 where purchase_no <= 4
group by buyer_id;

---

让我知道它是否有效。

此查询将提供买方id和日期范围内的购买数量：

DECLARE @from_dt datetime
DECLARE @Day_End_dt datetime
SET @from_dt =     '10/01/2010'
SET @Day_End_dt =  '12/29/2010' 

SELECT [buyer_id],COUNT([buyer_id]) AS purchases_in_period
  FROM [product_details]
  WHERE purchased_date_time between @from_dt and @Day_end_dt
  -- OPTIONAL LOCATION FILTER
  -- AND [location] = 'CA'
  GROUP BY [buyer_id]
GO

---

如果将其用作嵌套查询，则可以在给定的购买次数下计算买家id值。

我通常将其作为单独查询的联合

      select buyer from T,  1 as FirstTimeBuyer, 0 as SecondTimeBuyer, 0 as thirdtimebuyer
      where date is in the specified range
      group by buyer having count(t.id) = 1
      UNION
       select buyer from T,  0 as FirstTimeBuyer, 1 as SecondTimeBuyer, 0 as thirdtimebuyer
      where date is in the specified range
      group by buyer having count(t.id) = 2
      UNION
       select buyer from T,  0 as FirstTimeBuyer, 0 as SecondTimeBuyer, 1 as thirdtimebuyer
      where date is in the specified range
      group by buyer having count(t.id) = 3

---

您能提供您正在使用的DBMS以及示例输入/输出以增加清晰度吗？我使用的是MS SQL server 2000/2005/2008。谢谢，这是第一次买房吗？还是该日期范围内的第一次买家？。此外，您说您能够获得第一次买家，但在您的查询中，您正在对买家进行计数，而不是获得该数据范围内的买家、首次买家。抱歉搞混了，我在数买主。感谢我使用MS SQL server 2000/2005/2008。-真正地不，真的吗？嗨，Ronnis，我用输入输出样本编辑了我的问题。我现在正在测试您的查询。非常感谢汉克斯，罗尼斯。行数部分非常有用。@joe，我不明白第二/第三买家如何=7？您的样本数据中有5个不同的买家。1人购买产品2次id 9231374，1人购买产品3次id 8061088。我也不明白第四位或更多买家如何=3？只有2位买家购买了id 2288101和id 2510454的产品4次或4次以上。