How to get one output table from select in while-loop - sql

Question

Edited to live up to the rules here. Sorry about my first attempt.
I got the following sample data:
CREATE TABLE SampleData(
[Time] [time](7) NOT NULL
) ON [PRIMARY]
GO
INSERT INTO SampleData([Time]) VALUES ('01:00:00')
INSERT INTO SampleData([Time]) VALUES ('02:00:00')
INSERT INTO SampleData([Time]) VALUES ('02:00:00')
INSERT INTO SampleData([Time]) VALUES ('03:00:00')
INSERT INTO SampleData([Time]) VALUES ('03:00:00')
INSERT INTO SampleData([Time]) VALUES ('03:00:00')
INSERT INTO SampleData([Time]) VALUES ('04:00:00')
INSERT INTO SampleData([Time]) VALUES ('04:00:00')
INSERT INTO SampleData([Time]) VALUES ('04:00:00')
INSERT INTO SampleData([Time]) VALUES ('04:00:00')
GO
This is my query:
DECLARE #Counter INT
SET #Counter = 1
WHILE (#Counter <= 4)
BEGIN
SELECT Count([Time]) AS OrdersAmount
FROM SampleData
WHERE DATEPART(HOUR, [Time]) = #Counter
SET #Counter = #Counter + 1
END
This is the result of the query:
OrdersAmount
1
-----
OrdersAmount
2
-----
OrdersAmount
3
-----
OrdersAmount
4
So 4 seperate tables. What I need is one table, with alle values in it, on each their own row, like this:
OrdersAmount
1
2
3
4
I tried with cte and declaring a temp table, but I just can't make it work.

Answer 1

I don't have the data so can't test.
But if I get your problem right, this should work for you.
select PromisedPickupDt = cast(PromisedPickupDate as date),
[Hour] = datepart(hour, PromisedPickupDate),
HourlyAmount = sum(OrdersAmount)
from [FLX].[dbo].[NDA_SAP_Bestillinger]
where cast(PromisedPickupDate as date) = cast(getdate() as date)
group by cast(PromisedPickupDate as date), datepart(hour, PromisedPickupDate)

Answer 2

You need an Hours table to join and group against. You can create this using a VALUES constructor:
SELECT
Count(*) AS OrdersAmount
FROM (VALUES
(0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),(13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23)
) AS v(Hour)
LEFT JOIN [FLX].[dbo].[NDA_SAP_Bestillinger]
ON v.Hour = DATEPART(hour, PromisedPickupTime)
AND PromisedPickupDate >= CAST(CAST(GETDATE() AS date) AS datetime)
AND PromisedPickupDate < CAST(DATEADD(day, 1, CAST(GETDATE() AS date)) AS datetime)
GROUP BY v.Hour;
What is going on here is that we start with a filter by the current date.
Then we join a constructed Hours table against the hour-part of the date. Because it is on the left-side of a LEFT JOIN, we now have all the hours whether or not there is any value in that hour. We can now group by it.
Note the correct method to compare to a date range: a half-open interval >= AND <
Do not use YEAR\MONTH etc in join and filter predicates, as indexes cannot be used for this.