将枢轴上的计数转换为位/标志？

Question

我有一个有效的数据透视表查询：

SELECT * FROM
    (
        select [cid], [cid] as c, [Category] from [MyTbl] where [Conditional] = 0
    )
as src PIVOT(COUNT(c) FOR [Category] in ([SciFi],[Horror],[Comedy])) AS piv

太棒了，它会产生这样的东西：

cid | SciFi | Horror | Comedy
-----------------------------
 1      0        3       0
 2      1        2       1
 3      6        2       4

但实际上我不想要计数，我只想要一个 true 或 false 标志（最好是 0 或 1）

cid | SciFi | Horror | Comedy
-----------------------------
 1      0        1       0
 2      1        1       1
 3      0        1       1

我尝试在 case 语句中包装 count(c) 位，但我只是遇到语法错误 - 假设枢轴不是这样工作的。

Answer 1

我会推荐条件聚合。它比 vendor-specific pivot 语法灵活得多，可以让你轻松地做你想做的事：

select cid,
    max(case when category = 'SciFi'  then 1 else 0 end) SciFi,
    max(case when category = 'Horror' then 1 else 0 end) Horror,
    max(case when category = 'Comedy' then 1 else 0 end) Comedy
from mytbl
where conditional = 0
group by cid