如何将一行替换为多行而不是多行

Question

我有以下数据：

在SQL Server中如何按weekdate分组，因此每个weekdate只有一行，weekdate 2015-11-14 ：

  

有任何线索吗？

Answer 1

使用条件聚合。

select cast(weekdate as date), 
sum(case when permittype = 0 then total else 0 end) as permittype0,
sum(case when permittype = 1 then total else 0 end) as permittype1
from tablename
group by cast(weekdate as date)

Answer 2

我会使用条件聚合来做到这一点：

select weekdate,
       sum(case when permittype = 0 then total else 0 end) as permitttype0,
       sum(case when permittype = 1 then total else 0 end) as permitttype1
from followingdata t
group by weekdate
order by weekdate;

如果您愿意，也可以使用pivot语法。