SQL: Trying to understand IF/ELSE - sql

Question

SELECT CASE r.SourceId
WHEN '1' THEN 'ITUNES'
WHEN '2' THEN 'SFR'
WHEN '3' THEN 'ORANGE'
ELSE 'Others'
END as source
, CAST(SUM (r.SalesVolume) AS DECIMAL(14, 4) ) AS Volume
, CAST(SUM (r.SalesVolume * r.CustomerPrice) AS DECIMAL(14, 4) ) AS Value
from Rawdata r
INNER JOIN Product p
ON p.ProductId = r.ProductId
INNER JOIN Calendar c
ON r.DayId = c.DayId
WHERE c.WeekId BETWEEN (20145227) AND (20155230)
AND p.ContentFlavor IN ('SD', 'HD')
AND p.VODEST IN ('VOD','EST')
AND p.Distributor IN ('M6SND')
GROUP BY CASE r.SourceId
WHEN '1' THEN 'ITUNES'
WHEN '2' THEN 'SFR'
WHEN '3' THEN 'ORANGE'
ELSE 'Others'
END
The result of the above query is:
source Volume Value
ITUNES 48316.0000 506067.2600
This result is perfectly OK since my source table RawData doesnt contain any values for SourceId 2 or 3.
But what I basically want is the result to look like is:
source Volume Value
ITUNES 48316.0000 506067.2600
SFR 0 0
ORANGE 0 0
Others 0 0
If there is no value corresponding to any column parameter then I need it to be 0
I assume this could be done using IF/ELSE but not sure how?

Answer 1

with the help of a CTE this is a way to do it. (replace the first query with something more dynamic if you want)
with myChoices (choices)
as (
select
choices
from (
values
('ITUNES'),
('SFR'),
('ORANGE'),
('Others')
) [ ] (choices)
),
myQuery ([source],[Volume],[Value])
as (
SELECT CASE r.SourceId
WHEN '1' THEN 'ITUNES'
WHEN '2' THEN 'SFR'
WHEN '3' THEN 'ORANGE'
ELSE 'Others'
END as source
, CAST(SUM (r.SalesVolume) AS DECIMAL(14, 4) ) AS Volume
, CAST(SUM (r.SalesVolume * r.CustomerPrice) AS DECIMAL(14, 4) ) AS Value
from Rawdata r
INNER JOIN Product p
ON p.ProductId = r.ProductId
INNER JOIN Calendar c
ON r.DayId = c.DayId
WHERE c.WeekId BETWEEN (20145227) AND (20155230)
AND p.ContentFlavor IN ('SD', 'HD')
AND p.VODEST IN ('VOD','EST')
AND p.Distributor IN ('M6SND')
GROUP BY CASE r.SourceId
WHEN '1' THEN 'ITUNES'
WHEN '2' THEN 'SFR'
WHEN '3' THEN 'ORANGE'
ELSE 'Others'
END
)
select
c.choices,
ISNULL(q.Volume,0)Volume,
ISNULL(q.Value,0)Value
from myChoices c
left join myQuery q on
c.choices = q.[source]

Answer 2

Create an inline view called "Product_Inline_View", which is like
(select 1 as SourceId, 'ITUNES' as source_name
union all
select 2 as SourceId, 'SFR' as source_name
union all
select 3 as SourceId, 'ORANGE' as source_name
)
Right Join the Product_Inline_view with the Query you have, but without the CASE.
And then do the group by.