Question

我正在使用带有Microsoft SQL Server的VIsual Studio 2010，我正在尝试编写一个查询，该查询将按日期字段重新跟踪数据库中的（3）最新记录。以下是数据库中包含列的字段;

id | first_name | last_name |网址|日期

这是我正在使用的当前查询，但它只返回单个最近的条目;

SELECT        id, first_name, last_name, url, MAX(DISTINCT date) AS Expr1
FROM            tbl_paystubs
GROUP BY first_name
ORDER BY first_name

如何返回最近的（3）而不是（1）？

Answer 1

您可以找到最大值，然后找到小于最大值的下一个日期，然后找到小于该最大值的下一个日期。使用CTE：

WITH firstDate(id, first_name, last_name, url, date) 
as 
(
    SELECT        id, first_name, last_name, url, MAX(DISTINCT date) AS Expr1
    FROM            tbl_paystubs
    GROUP BY t.first_name, t.id, t.last_name, t.url
),
secondDate(id, first_name,Last_name,url,date)
(
    SELECT        t.id, t.first_name, t.last_name, t.url, MAX(t.date)
    FROM            tbl_paystubs t
    inner join firstDate f
    on f.id = t.id
    and f.first_Name = t.first_name
    and f.last_name = t.last_name
    and f.url = t.url 
    WHERE f.date > t.date
    GROUP BY t.first_name, t.id, t.last_name, t.url
),
thirdDate(id, first_name,Last_name,url,date)
(
    SELECT        t.id, t.first_name, t.last_name, t.url, MAX(t.date)
    FROM            tbl_paystubs t
    inner join secondDate s
    on s.id = t.id
    and s.first_Name = t.first_name
    and s.last_name = t.last_name
    and s.url = t.url 
    WHERE s.date > t.date
    GROUP BY t.first_name, t.id, t.last_name, t.url
)

   select f.id, 
          f.first_name, 
          f.last_name, 
          f.url, 
          f.date as "FirstMax", 
          s.date as "SecondMax", 
          t.date as "ThirdMax"
   from FirstDate f 
   left outer join SecondDate s
   on f.id = s.id
   and f.first_Name = s.first_name
   and f.last_name = s.last_name
   and f.url = s.url 
   left outer join ThirdDate t
   on f.id = t.id
   and f.first_Name = t.first_name
   and f.last_name = t.last_name
   and f.url = t.url

Answer 2

尝试这样的事情：

SELECT TOP 3 id, first_name, last_name, url, date
FROM tbl_paystubs
ORDER BY date desc

Answer 3

可以尝试

SELECT TOP 3  id, first_name, last_name, url, date
FROM            tbl_paystubs
ORDER BY date desc

只是重新查看你的代码并注意到Max（日期），最好的事情要做，简单的事情就是订购并选择前3

Answer 4

我的建议如下：

;with cte as(
SELECT       *
 ,ROW_NUMBER() over (partition by [date] order by [date]) as seq
FROM            tbl_paystubs
)
select Top 3 * from cte where seq= 1

CTE中的窗口函数，然后仅提取TOP 3记录

更新：我误解了这个问题，我认为OP正在寻找3个不同日期的3条记录。

如何使用日期字段选择3个最近的行

4 个答案: