Re: Ginq: combining join and aggregate functions

I figured out a workaround i.e. to do it in two steps:

def q =GQ {
   from sin sales
   join win warehouseon w.id == s.item select w.name, w.price }
assert [['Orange',11.0], ['Orange',11.0], ['Banana',4.0]] == q.toList()

def q2 =GQ {
   from win q
   groupby w.name orderby w.name in desc select w.name, sum(w.price)
}
assert [['Orange',22.0], ['Banana',4.0]] == q2.toList()

I submitted a feature request in Jira to support use of join, groupby and aggregate functions together.

Regards,
Per

On 10/5/24 19:16, Per Nyfelt wrote:
> Hi, I am trying to learn Ginq and are having problems with joining an 
> aggregation functions.
>
> The following example illustrates the issue:
>
> import java.time.LocalDate
>
> class Warehouse {
>     int id
>     String name
>     Double price
>     int stock
>
>     Warehouse(int id, String name, Double price, int stock) {
>       this.id = id
>       this.name = name
>       this.price = price
>       this.stock = stock
>     }
>   }
>
>   class Sales {
>     LocalDate date
>     int item
>
>     Sales(LocalDate date, int item) {
>       this.date = date
>       this.item = item
>     }
>   }
>
>
> List<Warehouse> warehouse = [
>     new Warehouse(1, 'Orange', 11, 2),
>     new Warehouse(2, 'Apple', 6, 3),
>     new Warehouse(3, 'Banana', 4, 1),
>     new Warehouse(4, 'Mango', 29, 10)
> ]
> List<Sales> sales = [
>     new Sales(LocalDate.of(2024, 5, 1), 1),
>     new Sales(LocalDate.of(2024, 5, 2), 1),
>     new Sales(LocalDate.of(2024, 5, 3), 3)
> ]
> def q = GQ {
>   from s in sales
>   join w in warehouse on w.id == s.item
>   select w.name, w.price
> }
> // so far so good, the following works:
> assert  [['Orange', 11.0], ['Orange', 11.0], ['Banana', 4.0]] == 
> q.toList()
>
> // now try to summarize by name
> def qSum = GQ {
>   from s in sales
>   join w in warehouse on w.id == s.item
>   groupby w.name
>   select w.name, sum(w.price)
> }
> // Fails with Exception evaluating property 'price' for 
> groovy.lang.Tuple2,
> // Reason: groovy.lang.MissingPropertyException: No such property: 
> price for class: Sales
> assert  [['Orange', 22.0], ['Banana', 4.0]] == qSum.toList()
>
> So for some reason ginq thinks it will find the price property in the 
> Sales class instead of in the Warehouse class so w.price here is not 
> understood. What is the right way to write it?
>
> Regards,
>
> Per
>