You need to flatten both D and E table. Then I suppose A and B are mere lookups for C, so there's no need to do GROUP BY on A: http://www.sqlfiddle.com/#!2/fccf1/8
I removed the noise(A and B), as I can't see(yet) how A and B are related to summarizing the information for C
Try this:
SELECT
C.Article,
C.Text,
COALESCE(D.ClicksSum,0) AS ClicksSum,
COALESCE(D.ImpressionsSum,0) AS ImpressionsSum,
COALESCE(E.ViewsSum,0) AS ViewsSum,
COALESCE(E.VisitorsSum,0) AS VisitorsSum
FROM
C
LEFT JOIN
(
SELECT TableC, SUM(Clicks) AS ClicksSum, SUM(Impressions) AS ImpressionsSum
FROM D
GROUP BY TableC
) D ON C.ID=D.TableC
LEFT JOIN
(
SELECT TableC, SUM(Views) AS ViewsSum, SUM(Visitors) AS VisitorsSum
FROM E
GROUP BY TableC
) E ON C.ID=E.TableC
Output:
| ARTICLE | TEXT | CLICKSSUM | IMPRESSIONSSUM | VIEWSSUM | VISITORSSUM |
----------------------------------------------------------------------------------
| Type | Unicode Art | 23 | 8 | 23 | 8 |
| Header | Spreadsheet | 15 | 10 | 32 | 21 |
| Auto Align | Off | 0 | 0 | 0 | 0 |
Note that I didn't type those schema in my sqlfiddle post manually, I uses sqlfiddle's Text to DDL
I love http://sqlfiddle.com, its Text to DDL can even parses out the data from your ASCII art ツ
Upon seeing your clearer objective(from your comment), this might be it: http://www.sqlfiddle.com/#!2/fccf1/13
SELECT
A.Name, A.Description,
COALESCE(SUM(D.ClicksSum),0) AS ClicksSum,
COALESCE(SUM(D.ImpressionsSum),0) AS ImpressionsSum,
COALESCE(SUM(E.ViewsSum),0) AS ViewsSum,
COALESCE(SUM(E.VisitorsSum),0) AS VisitorsSum
FROM
C
LEFT JOIN
(
SELECT TableC, SUM(Clicks) AS ClicksSum, SUM(Impressions) AS ImpressionsSum
FROM D
GROUP BY TableC
) D ON C.ID=D.TableC
LEFT JOIN
(
SELECT TableC, SUM(Views) AS ViewsSum, SUM(Visitors) AS VisitorsSum
FROM E
GROUP BY TableC
) E ON C.ID=E.TableC
RIGHT JOIN B ON B.ID = C.TableB
RIGHT JOIN A ON A.ID = B.TableA
GROUP BY A.ID
Output:
| NAME | DESCRIPTION | CLICKSSUM | IMPRESSIONSSUM | VIEWSSUM | VISITORSSUM |
----------------------------------------------------------------------------------
| Type | Unicode Art | 38 | 18 | 55 | 29 |
| Header | Spreadsheet | 0 | 0 | 0 | 0 |
| Auto Align | Off | 0 | 0 | 0 | 0 |
The above approach might still produce cartesian products, flatten the SubCategory(B) before grouping it to Category(A): http://www.sqlfiddle.com/#!2/fccf1/19
SELECT
A.Name, A.Description,
COALESCE(SUM(B.ClicksSum),0) AS ClicksSum,
COALESCE(SUM(B.ImpressionsSum),0) AS ImpressionsSum,
COALESCE(SUM(B.ViewsSum),0) AS ViewsSum,
COALESCE(SUM(B.VisitorsSum),0) AS VisitorsSum
FROM A
LEFT JOIN
(
SELECT
B.ID, B.TableA,
SUM(C.ClicksSum) AS ClicksSum,
SUM(C.ImpressionsSum) AS ImpressionsSum,
SUM(C.ViewsSum) AS ViewsSum,
SUM(C.VisitorsSum) AS VisitorsSum
FROM B
LEFT JOIN
(
SELECT
C.TableB,
D.ClicksSum,
D.ImpressionsSum,
E.ViewsSum,
E.VisitorsSum
FROM
C
LEFT JOIN
(
SELECT TableC, SUM(Clicks) AS ClicksSum, SUM(Impressions) AS ImpressionsSum
FROM D
GROUP BY TableC
) D ON C.ID=D.TableC
LEFT JOIN
(
SELECT TableC, SUM(Views) AS ViewsSum, SUM(Visitors) AS VisitorsSum
FROM E
GROUP BY TableC
) E ON C.ID=E.TableC
) C ON C.TableB = B.ID
GROUP BY B.ID
) B ON B.TableA = A.ID
GROUP BY A.ID
Output:
| NAME | DESCRIPTION | CLICKSSUM | IMPRESSIONSSUM | VIEWSSUM | VISITORSSUM |
----------------------------------------------------------------------------------
| Type | Unicode Art | 38 | 18 | 55 | 29 |
| Header | Spreadsheet | 0 | 0 | 0 | 0 |
| Auto Align | Off | 0 | 0 | 0 | 0 |