SQL Server 2014 - Case statement not exiting - sql

Question

I am having trouble writing a query to meet the following requirement. One point if Cust_3_3_a through Cust_3_3_c is selected, or Cust_3_3_f through Cust_3_3_h is selected, or Cust_3_4_ is selected; Zero points if Cust_3_3_e is selected and Cust_3_4_ is not selected with value '-'. Selected essentially means a the field has a value of a, b, c, etc.
Here is my test data and query. I would expect with 'Cust_3_4_' set to '-', that 0 should return but 1 returns instead. Is SQL not exiting the case when it hits 0 since the following check would return 1? Thanks in advance.
declare #test table (QuestionKey nvarchar(100), ResponseValue nvarchar(100))
insert into #test (QuestionKey, ResponseValue)
values
('Cust_3_3_a', ''), ('Cust_3_4_', '-'),
('Cust_3_3_b', ''),
('Cust_3_3_c', ''),
('Cust_3_3_e', 'a'),
('Cust_3_3_f', ''),
('Cust_3_3_g', ''),
('Cust_3_3_h', '')
select
max(case
when (
(t.questionkey = 'Cust_3_3_e' AND nullif(t.ResponseValue, '') IS NOT NULL)
and (t.questionkey = 'Cust_3_4_' AND nullif(t.ResponseValue, '') != '-')
) then 1
when (
(t.questionkey = 'Cust_3_3_e' AND nullif(t.ResponseValue, '') IS NOT NULL)
and (t.questionkey = 'Cust_3_4_' AND nullif(t.ResponseValue, '') = '-')
) then 0
when (
t.questionkey BETWEEN 'Cust_3_3_a' AND 'Cust_3_3_c'
OR t.questionkey BETWEEN 'Cust_3_3_f' AND 'Cust_3_3_h'
OR t.questionkey = 'Cust_3_4_'
) and nullif(t.ResponseValue, '') IS NOT NULL then 1
else 0
end) as test1
from #test t

Answer 1

Not sure what you want but I think you are confused with how case statement works. In order for you to return 0 for Cust_3_4_ where ResponseValue != '-', you need to have an actual row with QuestionKey = Cust_3_4_ and ResponseValue != '-' in your table (which you do not have in the above data set)
Also, you have applied MAX function outside your case so it will return you the maximum value 1 if any of the case condition returns 1. If you want the final result 0, you need to use MIN instead BUT please be aware that the 0 will be returned because of the following condition on Cust_3_3_e. Cust_3_4_ will have nothing to do with the 0
declare #test table (QuestionKey nvarchar(100), ResponseValue nvarchar(100))
insert into #test (QuestionKey, ResponseValue)
values
('Cust_3_3_a', ''), ('Cust_3_4_', '-'),
('Cust_3_3_b', ''),
('Cust_3_3_c', ''),
('Cust_3_3_e', 'a'),
('Cust_3_3_f', ''),
('Cust_3_3_g', ''),
('Cust_3_3_h', '')
select * from #test
order by 1 asc
select *,case when QuestionKey IN ('Cust_3_3_a','Cust_3_3_b','Cust_3_3_c') THEN 1
when QuestionKey = 'Cust_3_3_e' THEN 0
when QuestionKey IN ('Cust_3_3_f','Cust_3_3_g','Cust_3_3_h') THEN 1
when QuestionKey = 'Cust_3_4_' AND ResponseValue = '-' THEN 1
when QuestionKey = 'Cust_3_4_' AND ResponseValue <> '-' THEN 0
end test1
from #test