3 Statements into a view - sql

Question

I have 3 SQL statements that I would like to create a view and return 3 columns, each representing a count.
Here are my statements
SELECT Count(*)
FROM PlaceEvents
WHERE PlaceID = {placeID} AND EndDateTimeUTC >= GETUTCDATE()
SELECT Count(*)
FROM PlaceAnnouncements
WHERE PlaceID = {placeID}
SELECT Count(*)
FROM PlaceFeedback
WHERE PlaceID = {placeID} AND IsSystem = 0
I know how to create a basic view but how do I create one that will let me have those 3 column place placeID as a column to use for filtering
I would like to do the following to return the proper data
SELECT *
FROM vMyCountView
WHERE PlaceID = 1
CREATE VIEW vMyCountView AS
(...) AS ActiveEvents,
(...) AS Announcements,
(...) AS UserFeedback,
PlaceID

Answer 1

I'd rather use a function then a view:
This allows you to pass in any parameters you like (I assumed placeId is an INT) and deal with it within your query. The handling is quite as easy as with a View:
CREATE FUNCTION MyCountFunction(#PlaceID INT)
RETURNS TABLE
AS
RETURN
SELECT
(SELECT Count(*) FROM PlaceEvents WHERE PlaceID = #PlaceID AND EndDateTimeUTC >= GETUTCDATE()) AS ActiveEvents
,(SELECT Count(*) FROM PlaceAnnouncements WHERE PlaceID = #PlaceID) AS Announcements
,(SELECT Count(*) FROM PlaceFeedback WHERE PlaceID = #PlaceID AND IsSystem = 0) AS UserFeedback
,#PlaceID AS PlaceID;
GO
And this is how you call it. You can use this for JOINs or with APPLY also...
SELECT * FROM dbo.MyCountFunction(3);

Answer 2

You can combine them as multiple select sub-queries.
CREATE VIEW vMyCountView AS
SELECT
(SELECT Count(*) FROM PlaceEvents
WHERE PlaceID = s.placeID AND EndDateTimeUTC >= GETUTCDATE()) AS ActiveEvents,
(SELECT Count(*) FROM PlaceAnnouncements
WHERE PlaceID = s.placeID) AS Announcements,
(SELECT Count(*) FROM PlaceFeedback
WHERE PlaceID = s.placeID AND IsSystem = 0) AS UserFeedback,
placeID
from Sometable s

Answer 3

By definition, view is a single select statement. You can use join, union and so on if it makes sense to your business logic provided create view is the only query in the batch.

Answer 4

You can make a view like that with GROUP BY:
SELECT
PlaceId
, Count(peId) AS ActiveEvents
, COUNT(paId) AS Announcements
, COUNT(fbId) AS UserFeedback
FROM (
SELECT PlaceId, 1 AS peId, NULL AS paId, NULL AS fbId
FROM PlaceEvents
WHERE EndDateTimeUTC >= GETUTCDATE()
UNION ALL
SELECT PlaceId, NULL AS peId, 1 AS paId, NULL AS fbId
FROM PlaceAnnouncements
UNION ALL
SELECT PlaceId, NULL AS peId, NULL AS paId, 1 AS fbId
FROM PlaceFeedback
WHERE IsSystem = 0
) src
GROUP BY PlaceId
The idea behind this select, which is very easy to make into a view, is to select items from three tables into one for counting, and then group them all at once.
If you have two active events, one announcement, and three feedbacks for place ID 123, the three inner selects would produce this:
PlaceId peId paId fbId
------- ---- ---- ----
123 1 NULL NULL
123 1 NULL NULL
123 NULL 1 NULL
123 NULL NULL 1
123 NULL NULL 1
123 NULL NULL 1