在列列表中使用子查詢

Question

我想創建一個查詢，以計算在過去的7,14和28天內創建了多少條記錄。我的結果會返回類似於：

7Days 14Days 28Days 
21  35  56 

我知道如何爲每個時間安排例如7天，但我可以在一個查詢中捕獲所有三個？

select count(*) from Mytable 
where Created > DATEADD(day,-8, getdate()) 

Answer 1

而且不漂亮，但不依賴於子（表/列名來自AdventureWorks中）。如果它屬於你的標準內的情況下語句返回1，否則爲0 - 那麼你只總結的結果：

select sum(case when datediff(day, modifieddate, getdate()) <= 7 
       then 1 else 0 end) as '7days', 
     sum(case when datediff(day, modifieddate, getdate()) > 7 
        and datediff(day, modifieddate, getdate()) <= 14 
       then 1 else 0 end) as '14days', 
     sum(case when datediff(day, modifieddate, getdate()) > 14 
        and datediff(day, modifieddate, getdate()) <= 28 
       then 1 else 0 end) as '28days' 
from sales.salesorderdetail 

編輯：更新DATEDIFF函數 - 它是書面的方式，它會返回一個負數（假設修改日期過去）導致所有項目屬於第一種情況。感謝舍甫琴科M代表指出了這一點

Answer 2

這是不是世界上最漂亮的代碼，但它的伎倆。嘗試從三個子查詢中進行選擇，每個範圍一個。

select * from 
(select COUNT(*) as Cnt from Log_UrlRewrites where CreateDate >= DATEADD(day, -7, getdate())) as Seven 
inner join (select COUNT(*) as Cnt from Log_UrlRewrites where CreateDate >= DATEADD(day, -14, getdate())) as fourteen on 1 = 1 
inner join (select COUNT(*) as Cnt from Log_UrlRewrites where CreateDate >= DATEADD(day, -28, getdate())) as twentyeight on 1 = 1 

Answer 3

select 
(
    select count(*) 
    from Mytable 
    where Created > DATEADD(day,-8, getdate()) 
) as [7Days], 
(
    select count(*) 
    from Mytable 
    where Created > DATEADD(day,-15, getdate()) 
) as [14Days], 
(
    select count(*) 
    from Mytable 
    where Created > DATEADD(day,-29, getdate()) 
) as [28Days] 

Answer 4

SELECT 
    [7Days] = COUNT(CASE UtmostRange WHEN 7 THEN 1 END), 
    [14Days] = COUNT(CASE UtmostRange WHEN 14 THEN 1 END), 
    [28Days] = COUNT(CASE UtmostRange WHEN 28 THEN 1 END) 
FROM (
    SELECT 
    *, 
    UtmostRange = CASE 
     WHEN Created > DATEADD(day, -8, GETDATE()) THEN 7 
     WHEN Created > DATEADD(day, -15, GETDATE()) THEN 14 
     WHEN Created > DATEADD(day, -29, GETDATE()) THEN 28 
    END 
    FROM Mytable 
) s