T-SQL 动态查询和数据透视

Question

我有数据表明人们在月中改变了角色，并希望在新的开始日期之后计算 activity。我可以使用 table 的结果作为动态查询吗，我有一个 returns 以下结果集的查询：-

Firstname    Surname    StartDate
----------------------------------
Jon          Smith      2015-01-01
Paul         Jones      2014-07-23
...

所以查询看起来像这样：

SELECT Firstname +' '+ surname, month,  count(1) FROM dataTable
WHERE (Firstname='John' AND Surname='Smith' AND date >=2015-01-01)
OR (Firstname='Paul' AND Surname='Jones' AND date >=2014-07-23)
OR ...

但 'ORs' 的数量取决于第一个 table

中的行数

Name        Month   Count
----------------------------------
Jon Smith   1       15
Paul Jones  1       16
Jon Smith   2       30
Paul Jones  2       25
Charlie Gu  1       52

然后我可以旋转得到

Name          1      2
--------------------------
Jon Smith     15     30
Paul Jones    16     25
Charlie Gu    52     NULL

提前致谢

Answer 1

在我看来 Ako 是正确的，简单的连接应该可以解决问题，而不是动态查询。

declare @NewStartDates table
    (
     Firstname nvarchar(100),
     Surname nvarchar(100),
     StartDate date
    );

insert  into @NewStartDates
        (Firstname, Surname, StartDate)
values  (N'Jon', N'Smith', '20150101'),
        (N'Paul', N'Jones', '20140723');

select  d.Firstname,
        d.Surname,
        year(d.Date) * 100 + month(d.Date) as Period,
        count(*) as ActivityCount
from    dataTable as d
inner join @NewStartDates as n
        on d.Firstname = n.Firstname
           and d.Surname = n.Surname
           and d.Date >= n.StartDate
group by d.Firstname,
        d.Surname,
        year(d.Date) * 100 + month(d.Date);

Answer 2

请参考这个 - 它会让您完整了解如何获得动态列查询。

T-SQL 动态查询和数据透视

T-SQL Dynamic Query and pivot

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