Traceability Status Chart (requirement coverage) in Enterprise Architect

I'm struggling in creating a chart to show traceability status using EA v15.0 I have defined a model (eapx file) with two stereotypes "Customer Requirement" and "Software Requirement" which shall be linked together via Realization link.

The main objective is to obtain a chart like showing as YES (Covered) the Customer Requirements that have at least one realization link to a Software Requirement, NO (Uncovered) otherwise.

Do you have any suggestion to create this? I think a Custom SQL would do the job...

I have already created some SQL queries to get the list of Covered Customer Requirements (and similarly for the Uncovered ones) as ModelView elements, using the following SQL query:

SELECT t_object.ea_guid AS CLASSGUID, t_object.Object_Type AS CLASSTYPE, t_object.Name AS [Requirement], t_package.Name AS Package, t_object.Status, t_object.Stereotype 
FROM t_package 
INNER JOIN t_object ON t_package.Package_ID=t_object.Package_ID 
WHERE t_object.Object_ID IN 
(
    SELECT t_connector.End_Object_ID 
    FROM t_connector 
    INNER JOIN t_object on t_connector.Start_Object_ID = t_object.Object_ID
    WHERE t_connector.connector_Type='Realisation'
    AND t_object.Stereotype = 'Software Requirement'
) 
AND t_object.Stereotype='Customer Requirement' 

and I obtain a list of elements like

However, for reporting purposes, I would like to summarize the requirements coverage status in a chart. I think this could be realized with a Standard Chart using a Custom SQL as Source, but I'm not able to define the SQL query.

With a query like this it should work.
You are looking for two sets:

A) the customer requirements that are realized by a software requirement. These are represented in the first query by Realized

B) the customer requirements that are realized by a software requirement. These are represented in the first query by Not Realized

Both queries are joined using a union all. EA then simply counts the Realized and non Realised and puts them in the pie chart.

select 'Realized' AS Series  
from t_object o
where o.Stereotype = 'Customer Requirement' 
and exists 
    (select o.ea_guid from (t_object rq
    inner join t_connector c on (c.Start_Object_ID = rq.Object_ID
                            and c.Connector_Type = 'Realisation'))
    where rq.Stereotype = 'Software Requirement'
    and c.End_Object_ID = o.Object_ID)
union all
select 'Not Realised' AS Series  
from t_object o
where o.Stereotype = 'Customer Requirement' 
and not exists 
    (select o.ea_guid from (t_object rq
    inner join t_connector c on (c.Start_Object_ID = rq.Object_ID
                            and c.Connector_Type = 'Realisation'))
    where rq.Stereotype = 'Software Requirement'
    and c.End_Object_ID = o.Object_ID)