sql - 每小时每种类型的 SQL 计数

Question

希望计算一个小时内记录的类型数量。

我可以用这段代码计算类型的数量：

SELECT count (left (Barcode,9)) as T_Count, left (Barcode,9) as T
FROM table
group by left (Barcode,9)

并且可以使用此代码（包括所有类型）计算每小时的项目数：

SELECT Year, Month, Day, Hour, COUNT(T) AS "Items per Hour"
FROM
(
SELECT DATEPART(YEAR,timestamp) Year, DATEPART(MONTH,timestamp) Month,
DATEPART(DAY,timestamp) Day, DATEPART(HOUR, timestamp) Hour, left (Barcode,9) as T
FROM table
) temp
group by Year, Month, Day, Hour
order by Year desc, Month desc, Day desc

但是不知道如何计算每小时每种类型的项目数 - 这意味着一个小时内将有超过 1 个条目 - 根据类型的数量...

Answer 1

SELECT 
    Year, Month, Day, Hour, 
    COUNT(T) AS "Items per Hour", 
    count (distinct T) as "Types per Hour"
FROM 
    ( SELECT DATEPART(YEAR,timestamp) Year, DATEPART(MONTH,timestamp) Month, DATEPART(DAY,timestamp) Day, DATEPART(HOUR, timestamp) Hour, left (Barcode,9) as T FROM [JCI_Trim].[dbo].[T6_Trim] ) temp 
group by Year, Month, Day, Hour 
order by Year desc, Month desc, Day desc