Decision Management Notation (DMN) Grouping/Aggregation of List Data

[ghdunn]

I am just getting started with Decision Management Notation (DMN), using a free trial of Trisotech DMN which in general terms I am liking a lot.  I am waiting to receive the Silver book DMN Method and Style from Amazon but its not here yet and not sure if it will cover this question:

I can't really overcome what appears to me to be a basic issue.  Maybe I am just not grasping some fundamental comments. representing the aggregation of list data in an elegant way...similar to how I would do it in SQL

If I have athletics high jump event data:

Results

Competitor	Attempt	Height
a	1	170
a	2	185
a	3	165
b	1	128
b	2	180
b	3	190
c  etc	0	0

In MS Access SQL, to generate the ranked list of winners 

SELECT Results.Competitor, Max(Results.Height) AS MaxOfHeight
FROM Results
GROUP BY Results.Competitor
ORDER BY Max(Results.Height) DESC;  

To represent this in DMN, intuitively I am thinking I might create a data type called 'Results', with three fields, and then assign that to an Input Data Input object.  I would then link that Data Input object to a Decision Object and write some similar code to the SQL

Is this the way I should be thinking about grouping/aggregating list data?

I don't know if the XML will mean anything to anyone but this is my effort so far, including me trying to add some 'pseudocode' expression to match the SQL 

<semantic:definitions
xmlns:semantic="http://www.omg.org/spec/DMN/20180521/MODEL/" id="_7e6515d4-dcb0-4652-8fc9-cfc948f1640b" name="Drawing 1"
xmlns:triso="http://www.trisotech.com/2015/triso/modeling" triso:logoChoice="Default" exporterVersion="6.1.17.1" exporter="DMN Modeler"
xmlns:tc="http://www.omg.org/spec/DMN/20160719/testcase" 
xmlns:feel="http://www.omg.org/spec/DMN/20180521/FEEL/" 
xmlns:dmndi="http://www.omg.org/spec/DMN/20180521/DMNDI/" 
xmlns:di="http://www.omg.org/spec/DMN/20180521/DI/" 
xmlns:dc="http://www.omg.org/spec/DMN/20180521/DC/" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:trisofeed="http://trisotech.com/feed" 
xmlns="http://www.trisotech.com/definitions/_7e6515d4-dcb0-4652-8fc9-cfc948f1640b" namespace="http://www.trisotech.com/definitions/_7e6515d4-dcb0-4652-8fc9-cfc948f1640b">
 
<semantic:extensionElements />
   
<semantic:itemDefinition name="Results" label="Results">
 
<semantic:itemComponent id="_ccbada40-3038-46f0-b983-3603abdeccd8" name="Competitor">
   
<semantic:typeRef>string</semantic:typeRef>
 
</semantic:itemComponent>
   
<semantic:itemComponent id="_67903a3f-e80e-40bb-87ad-a04f38d199c0" name="Attempt">
       
<semantic:typeRef>number</semantic:typeRef>
     
</semantic:itemComponent>
   
<semantic:itemComponent id="_57316736-a020-46dc-a383-23f86c4a64c7" name="Height">
     
<semantic:typeRef>number</semantic:typeRef>
   
</semantic:itemComponent>

</semantic:itemDefinition>
  
<semantic:inputData id="_a14bfe06-7b6c-4827-bcb8-7365ceb6f0b2" name="">
   
<semantic:variable id="_d1cad4e8-dd84-4db6-885e-386853614322" name="" typeRef="Results" />
 
</semantic:inputData>
 
<semantic:decision id="_46dce6a8-e8cb-492b-86d2-e3c9f7746059" name="Decision Logic 1">
   
<semantic:variable id="_91a4e0d6-1ac6-41bf-b153-8cafea54d8cb" name="Decision Logic 1" typeRef="Any" />
 
<semantic:informationRequirement id="_5c2d09d5-8069-4b32-b757-fd01906aad31">
         
<semantic:requiredInput href="#_a14bfe06-7b6c-4827-bcb8-7365ceb6f0b2" />
     
</semantic:informationRequirement>
  
<semantic:literalExpression id="_7c51851e-87b8-4ae7-b556-d46c8a97592d" typeRef="Any" triso:expressionId="_45f12004-f388-4ed4-84c6-f1c584273281">
      
<semantic:text>max("Results.Height") "group by Results.Competitor"</semantic:text>
 
</semantic:literalExpression>
 
</semantic:decision>

<dmndi:DMNDI>
    
<dmndi:DMNDiagram id="_5a072066-c95d-4f99-a1ae-7422649c5626" name="Page 1">
       
<dmndi:Size width="1485" height="1050" />
      
<dmndi:DMNShape id="_bc906a06-f82a-4d50-aae2-9e8aad117a85" dmnElementRef="_a14bfe06-7b6c-4827-bcb8-7365ceb6f0b2">
  
<dc:Bounds y="186" x="300.2982659339905" width="135.40346813201904" height="60" />
              
<dmndi:DMNLabel sharedStyle="LS_7e6515d4-dcb0-4652-8fc9-cfc948f1640b_0" />
    
</dmndi:DMNShape>
       
<dmndi:DMNShape id="_1cc64c87-2b03-44ad-935e-04d259a4732c" dmnElementRef="_46dce6a8-e8cb-492b-86d2-e3c9f7746059">
     
<dc:Bounds y="23" x="449.5" width="153" height="60" />
          
<dmndi:DMNLabel sharedStyle="LS_7e6515d4-dcb0-4652-8fc9-cfc948f1640b_0" xmlns:trisodmn="http://www.trisotech.com/2016/triso/dmn" trisodmn:defaultBounds="true">
     
<dc:Bounds y="46.67500019073486" x="452.5" width="146" height="12.649999618530273" />
           
</dmndi:DMNLabel>
 
</dmndi:DMNShape>
    
<dmndi:DMNEdge id="_e14ec571-9cc3-4c56-8de5-1dcf10f3a2e7" dmnElementRef="_5c2d09d5-8069-4b32-b757-fd01906aad31">
         
<di:waypoint y="186" x="367.9941382408142" />
       
<di:waypoint y="83" x="516" />
            
<dmndi:DMNLabel sharedStyle="LS_7e6515d4-dcb0-4652-8fc9-cfc948f1640b_0" />
    
</dmndi:DMNEdge>
    
</dmndi:DMNDiagram>
    
<dmndi:DMNStyle id="LS_7e6515d4-dcb0-4652-8fc9-cfc948f1640b_0" fontFamily="arial,helvetica,sans-serif" fontSize="11" fontBold="false" fontItalic="false" fontUnderline="false" fontStrikeThrough="false" />
  
</dmndi:DMNDI>

</semantic:definitions>