SQL Select case

Question

I have the following sql tables

oitems table

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


        

Answer 1

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