case when with count and combining similar values in sql

1SELECT 
2    data.id,
3    data.lastname,
4    data.firstname,
5    SUM(data.WebData) AS WebData,
6    SUM(data.InternalData) AS InternalData,
7    SUM(data.countid) AS Countid
8FROM
9    (
10       SELECT id,lastname,
11              firstname,datasource,
12              CASE WHEN Datasource = 'Web' THEN Count(Datasource) ELSE 0 END WebData,
13              CASE WHEN Datasource = 'Internal' THEN Count(Datasource)ELSE 0 END InternalData,
14             count(id) AS Countid
15
16        FROM Table
17        GROUP BY
18                 id,lastname,firstname,datasource
19     ) AS data
20GROUP BY 
21    data.id,data.firstname,data.lastname