SQL Sum with conditions in a select case

Question

have the following sql query

select catalogid
   , sum(numitems) numitems
   , sum(allitems) - sum(numitems) ignoreditems
from
(
   select i.catalogid
      , case
           when (ocardtype in ('PayPal','Sofort') OR
                   ocardtype in ('mastercard','visa') and
                   odate is not null)
              AND NOT EXISTS
              (
                 select *
                 FROM bookedordersids b
                 where b.booked = o.orderid
              )
           then numitems
           else 0
        end AS numitems
      , numitems AS allitems
   from orders AS o
   join oitems AS i on i.orderid = o.orderid
) AS X
group by catalogid

now i've 2 tables Here orders and oitems table

the query sums the numitems and ignoreditems based on the conditions you see, now what if i want to find the sum only when the value of a column called oprocessed in oitems table is 0 ,

do i add the following before X

where oprocessed=0

or should i add a condition to the SELECT CASE?

Answer 1

Your catalog id is coming from the oitems table - adding where oprocessed=0 would mean that those catalog numbers aren't included in your results.

My guess is you'd therefore want this in your case statement - but I'm not entirely sure on the spec behind this so can't say for sure.

select catalogid
, sum(numitems) numitems
, sum(allitems) - sum(numitems) ignoreditems
from 
(
    select i.catalogid
    , numitems allitems
    , case 
        when --if the money for the order is gaurenteed return the number of items bought
        (
            ocardtype in ('PayPal','Sofort') 
            OR
            (
                ocardtype in ('mastercard','visa') 
                and
                odate is not null
            )
        ) 
        AND NOT EXISTS 
        (
            select top 1 1
            FROM bookedordersids b
            where b.booked = o.orderid
        )
        and i.oprocessed = 0
        then numitems
        else 0 --if payment isn't made/gaurenteed 0 items bought
    end numitems
    from orders o
    inner join oitems i 
    on i.orderid = o.orderid
) X
group by catalogid