Question

I am writing down a view in SQL server (DWH) and the use case pseudo code is:

-- Do some calculation and generate #Temp1
-- ... contains other selects

-- Select statement 1
SELECT * FROM Foo
JOIN #Temp1 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1

-- Do some calculation and generate #Temp2
-- ... contains other selects

-- Select statement 2
SELECT * FROM Foo
JOIN #Temp2 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1

The result of the view should be:

Select Statement 1
UNION
Select Statement 2

The intended behavior is the same as the yield returnin C#. Is there a way to tell the view which SELECT statements are actually part of the result and which are not? since the small calculations preceding what I need also contain selects.

Thank you!

Answer 1

I found a better work around. It might be helpful for someone else. It is actually to include all the calculation inside WITH statements instead of doing them in the view core:

WITH Temp1 (ID)
AS
(
    -- Do some calculation and generate #Temp1
    -- ... contains other selects
)

, Temp2 (ID)
AS
(
    -- Do some calculation and generate #Temp2
    -- ... contains other selects
)

-- Select statement 1
SELECT * FROM Foo
JOIN Temp1 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1

UNION

-- Select statement 2
SELECT * FROM Foo
JOIN Temp2 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1

The result will be of course the UNION of all the outiside SELECT statements.