case statement returns multiple rows

Question

I want to return multiple rows in case statement. is it possible? or is there any alternate way to do it?

select 
   case 
      when 3 = 1 
          then (select orderid from order_master where noOfInstallment = installmentPaid) 
      else 
          (select orderid from order_master where noOfInstallment <> installmentPaid) 
   END

Both sub queries returns multiple rows. Now above query showing following error.

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

Answer 1

I got solution.

 SELECT o.* FROM Order_Master as o Where 
   (
      ((@paymentStatus = 0) AND (o.noOfInstallment <> o.installmentPaid))
      OR 
      ((@paymentStatus=1) AND (o.noOfInstallment = o.installmentPaid)) 
   )

Answer 2

CASE in SQL Server is not a flow control statement (it's different than the switch statement in C#) - it's just used to return one of several possible values.

You need to use IF statements in T-SQL

IF 3 = 1
   select orderid from order_master where noOfInstallment = installmentPaid
ELSE
   select orderid from order_master where noOfInstallment <> installmentPaid

or something like this.

Answer 3

You are not using the case statement in a right way, please take alook at the documentation.

Can you manage with a query like this:

select orderid,  
   case 
      when (noOfInstallment = installmentPaid) then
        'equal'   
      else 
        'not equal'
   END
from order_master