Question

given the following table definition

I have a query written as so:

select id,  
(  
   case   
      when partial >= 2 and full >=2  
      then sum(partial+full)  
      when partial >=2   
      then partial  
      when full >= 2  
      then full  
      else 0 
   end  
) counts
from Foo

What is the minimum number of checks that I have to do to ensure that the inner when clauses:

partial>=2 and full >=2 are not invoked twice. That is does the case when/then syntax treat everything as else ifs and not just straight ifs?

Answer 1

You can do

select id,  
(  
   case when partial >= 2 then partial else 0 end + 
   case when full >= 2 then full else 0 end  
) counts
from Foo

Sample SQL FIDDLE