SQL in IT shop - Filter on candidate objects

I want to use Filter to show items in a list (Database column selection).

I want to use complex query that looks like 

Variable ("UID_ParentOrg IN (

select BU =

case

when(

              SELECT count(O.UID_ParentOrg)

              FROM Person U /* Filter on the ParentOrg of the creator of the user */

              JOIN Org O ON U.UID_Org = O.UID_Org

              WHERE U.UID_Person = '%useruid%'

              and UID_OrgRoot IN (

                     SELECT O.UID_OrgRoot

                     FROM Org O /* Filter on the Job Title */

                     join OrgRoot RO on RO.UID_OrgRoot = O.UID_OrgRoot

                     where Ident_OrgRoot = 'CCC-JobTitles'

              )) < 1

              /* If Title is assigned */

       THEN

       (

              SELECT O.UID_Org

              FROM Org O /* Filter on the ParentOrg of the creator of the user */

              Where

              O.Ident_Org in (

                     select distinct D1.DepartmentNAme

                     from Person P

                     join Department D on D.UID_Department=P.UID_Department

                     join Department D1 on D1.UID_Department=D.UID_PArentDepartment

                     where

                     P.UID_Person = '%useruid%'

                     ) 

              and fullpath like 'CCC-JobTitles%'  

       )     

       ELSE

       (

              SELECT O.UID_ParentOrg

              FROM Person U /* Filter on the ParentOrg of the creator of the user */

              JOIN Org O ON U.UID_Org = O.UID_Org

              WHERE U.UID_Person = '%useruid%'

              and UID_OrgRoot IN (

                     SELECT O.UID_OrgRoot

                     FROM Org O /* Filter on the Job Title */

                     join OrgRoot RO on RO.UID_OrgRoot = O.UID_OrgRoot

                     where Ident_OrgRoot = 'CCC-JobTitles'

              )

       )

       END

)")

When I open the page where selection should be visible There is just loading icon. After some time (few minutes) I get error 

    SyntaxError: Unexpected token < in JSON at position 2

In case I use simplified version of above SQL

Variable ("UID_ParentOrg IN (

select BU =

case

when( 1=1 ) 

       THEN

       (

              SELECT BU = 'e39aed0d-c3a0-48a9-998b-1a77af2f85af'

       )     

       ELSE

       (

              SELECT BU ='e39aed0d-c3a0-48a9-998b-1a77af2f85ae'

       )

       END

   )")

Everything is working as expected.

Are there any limitations on writing query?

Many thanks for suggestions