SQL query with multiple/embedded CASE - sql-server-2012

Question

I am stuck in a query; if you have time can you let me know how to fix it?
I have a (hypothetical) table with TypeID, SubTypeID, Option1, Option2 and Option3 columns; last three columns are Boolean.
So, I might have something like this:
TypeID SubTypeID Option1 Option2 Option3
1 5 false false false
2 0 true false false
2 0 false true true
2 0 true true true
What I am trying to get, in case TypeID=2 is the following, using example above:
'Option 1'
'Option 2, Option 3'
'Option1, Option 2, Option 3'
I tried this but getting syntax error and I am not even sure it is correct:
case when fd.TypeID=1 then ft.SubType else (case when fd.Option1=1 then 'Option 1,' else (case when fd.Option2=1 then 'Option 2,' else (case when fd.Option3=1 then 'Option 3' else '' ))) as SubType,

Answer 1

You could use IIF/CASE:
SELECT
IIF(Option1='true', 'Option 1,', '') +
IIF(Option2='true', 'Option 2,', '') +
IIF(Option3='true', 'Option 3,', '') AS Output
FROM table_name
WHERE TypeId = 2;
If you don't like final comma you could remove it with:
WITH cte AS (
SELECT
IIF(Option1='true', 'Option 1,', '') +
IIF(Option2='true', 'Option 2,', '') +
IIF(Option3='true', 'Option 3,', '') AS Output
FROM table_name
WHERE TypeId = 2
)
SELECT LEFT(Output, len(Output)-1)
FROM cte
WHERE Output <> '';
EDIT:
How would I enclose this inside a CASE? Something like: CASE WHEN TypeId=1 THEN something ELSE (your statements)? When I try it I get a bunch of syntax errors.
Simply:
SELECT
CASE WHEN Option1='true' THEN 'Option 1,' ELSE '' END +
CASE WHEN Option2='true' THEN 'Option 2,' ELSE '' END +
CASE WHEN Option3='true' THEN 'Option 3,' ELSE '' END AS Output
FROM table_name
WHERE TypeId = 2;

Answer 2

If you want the options with no comma in the middle, then I think the easiest way is:
select stuff( ((case when option1 = 'true' then ', Option1' else '' end) +
(case when option2 = 'true' then ', Option2' else '' end) +
(case when option3 = 'true' then ', Option3' else '' end)
), 1, 2, ''
) as option_list
from t;
If you only want this for one of the types:
select (case when type = 1
then select stuff( ((case when option1 = 'true' then ', Option1' else '' end) +
(case when option2 = 'true' then ', Option2' else '' end) +
(case when option3 = 'true' then ', Option3' else '' end)
), 1, 2, ''
)
end) as option_list
from t;