Case Statement with different data type

Question

I am trying to return SLA days for particular conditions. However for a specific condition I want it to return a different data type. Current code is as follows:

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Answer 1

A case statement can only return one data type. So convert the numbers to strings:

SELECT CASE
  WHEN fourthlevel.case_type IN ('Complaint')
  THEN
     (SELECT cast(COUNT(*) as varchar2(255))
        FROM work_days1
       WHERE     work_days1.business_date > fourthlevel.cdate
             AND work_days1.business_date <=
                    COALESCE (fourthlevel.close_date, SYSDATE))
  WHEN fourthlevel.case_type IN ('Enquiry')
  THEN
     (SELECT cast(COUNT(*) as varchar2(255))
        FROM work_days1
       WHERE     work_days1.business_date > fourthlevel.create_date
             AND work_days1.business_date <=
                    COALESCE (fourthlevel.close_date, SYSDATE))
  WHEN fourthlevel.case_status = 'Cancelled'
  THEN
     'N/A'
END AS sla_days
FROM fourthlevel

Alternatively, you could return NULL when the two conditions do not match.