Oracle select query with dynamic in clause - sql

Question

I have the following query
select * from table_1
where Conditions in
(select case when check_condition = 'Y' then 'Condition_1'
else 'N/A' end as Check_condition
from table_2
WHERE id = 1122)
where table_1 contains the values in column Conditions as follows.
Condition_1,Condition_2
This works fine and return me the results.
i want to use multiple select statements inside the in clause and I did it as below.
select * from table_1
where Conditions in (
select ''''||
(select case when check_condition = 'Y' then 'Condition_1'
else 'N/A' end as Check_condition
from table_2
WHERE id = 1122)||''''||','''||
(select case when check_condition = 'Y' then 'Condition_2'
else 'N/A' end as Check_condition
from table_2 WHERE id = 1122)||''''
from dual
)
inner query ( inside the in clause) giving me the correct results as expected -
'Condition_1','Condition_2'
and when I copy paste it to the parent query it works fine and show the results.
select * from table_1 where Conditions in ('Condition_1','Condition_2')
My issue is, it is not giving any results when I used the second query. I know that sub query will return the results that should match the rows in the outer query. But it shows me empty result set.
I am using oracle 11g
Can anyone please help me out.. Thank you all in advance.

Answer 1

The question is a bit unclear regarding requirements. What I think you want is to select records from table1 only when:
rows match 'Condition_1' or 'Condition_2'
check_condition = 'Y'
there is a row in table2 with an ID = 1122
It's not clear from your question whether check_condition is a column or a variable, and if it is a column to which table it belongs. Consequently this solution may be wrong but it illustrates the principle.
select * from table1 t1
where t1.conditions in ('Condition_1','Condition_2')
and t1.check_condition = 'Y'
and exists
( select null from table2 t2
where t2.id = 1122 )
If this doesn't provide the solution you need please revise your question so it states the business logic you need to implement, and also includes relevant tables descriptions.

Answer 2

You aren't ending up with two values passed into the in clause like when you do it manually:
select * from table_1 where Conditions in ('Condition_1','Condition_2')
You're passing a single value which is the concatenation of the values:
select * from table_1 where Conditions in ('''Condition_1'',''Condition_2''')
And no condition matches that concatenated value, so you get no results. You could do something like:
select * from table_1 where Conditions in (
select case when check_condition = 'Y' then 'Condition_1' else 'N/A' end
from table_2 WHERE id = 1122
union all
select case when check_condition = 'Y' then 'Condition_2' else 'N/A' end
from table_2 WHERE id = 1122
)
Or possibly, if I follow what you're doing (which is doubtful as I'm not sure I understand your data model!):
select * from table_1 where check_condition != 'Y' or Conditions in (
select 'Condition_1' from table_2 WHERE id = 1122
union all
select 'Condition_2' from table_2 WHERE id = 1122
)
It seems like you should be able to do this more cleanly, with joins, but I think we'd need to see the structures and sample data to understand what's going on a bit more.