SQL Select case

Question

I have the following sql tables

oitems table

    +---------+-----------+----------+
    | orderid | catalogid | numitems |
    +---------+-----------+------         


        

Answer 1

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

Answer 2

Something like:

SELECT
     oi.catalog_id,
     SUM(CASE
            WHEN ocardtype in ('Paypal','Sofort') THEN numitems
            WHEN ocardtype in ('Mastercard','Visa') and odate is not null THEN numitems
            ELSE 0 END) as numitems,
     SUM(CASE
            WHEN ocardtype is null then numitems
            WHEN ocardtype in ('Mastercard','Visa') and odate is null THEN numitems
            ELSE 0 END) as ignoreditems
FROM
   oitems oi
      inner join
   Orders o
      on
         oi.orderid = o.orderid
GROUP BY
   oi.catalog_id

(Assuming that wherever you've used the word "empty" in your narrative, you mean the column is NULL)

Answer 3

Here is a Linq-to-sql version of your original request (as a LINQpad query):

Dim odateRequired = {"MasterCard", "Visa"}
Dim odateNotRequired = {"Paypal", "Sofort"}
Dim result = From o In Orders Join i In Oitems On o.orderid Equals i.orderid _
             Let check = o.ocardtype IsNot Nothing _
                     AndAlso ((odateRequired.Contains(o.ocardtype) _
                               AndAlso o.odate IsNot Nothing) _
                        OrElse odateNotRequired.Contains(o.ocardtype)) _
         Group By i.catalogid Into _
         numitem = Sum(If(check, i.numitems, 0)), _
         ignored = Sum(If(check, 0, i.numitems))

result.Dump

Your extra request in the comments to RichardTheKiwi's answer (it just includes Not (From b In Bookeds Where b.ignoredoid=i.orderid).Any AndAlso at the front of the check):

Dim odateRequired = {"MasterCard", "Visa"}
Dim odateNotRequired = {"Paypal", "Sofort"}
Dim result = From o In Orders Join i In Oitems On o.orderid Equals i.orderid _
             Let check = Not (From b In Bookeds Where b.ignoredoid = i.orderid).Any _
                     AndAlso o.ocardtype IsNot Nothing _
                     AndAlso ((odateRequired.Contains(o.ocardtype) _
                               AndAlso o.odate IsNot Nothing) _
                        OrElse odateNotRequired.Contains(o.ocardtype)) _
         Group By i.catalogid Into _
         numitem = Sum(If(check, i.numitems, 0)), _
         ignored = Sum(If(check, 0, i.numitems))

result.Dump