SQL Server Select 語句列

Question

原始查詢：

select StudyID, count(CompletedDate), count(Removed), count(RemovalReason)
from Study a
full outer join Households b
on a.HouseholdID = b.HouseholdID
where StudyID = '123456'
and Removed = 1
and RemovalReason = 5
group by StudyID

我如何寫出此查詢，以便對於每一列（CompletedDate、Removal 和 RemovalReason）不受條件限制（即 Removed = 1、Removal Reason = 5）並且僅適用於特定列。 如果我執行此查詢，它不會顯示 CompletedDate 的總數，因為我將其限制為這些條件。 有沒有辦法直接寫在count旁邊？

表/列 - 研究：HouseholdID（主鍵）、StudyID、CompletedDate

表/列 - 家庭：HouseholdID（主鍵）、已刪除、RemovalReason

Answer 1

我認為您正在尋找這樣的東西，但您的問題在細節上有點松散：

select StudyID
    , count(CompletedDate)
    , sum(case when Removed = 1 then 1 else 0 end)
    , sum(case when RemovalReason = 5 then 1 else 0 end)
from Study a
  join Households b
       on a.HouseholdID = b.HouseholdID
where StudyID = '123456'
group by StudyID