SQL SUM Values need and then AVG of 2 Tables - sql-server

Question

From this it is possible for the following :
TABLE 1
Id | final | Date
------------------
1 236 02-11-14
2 10 07-01-12
3 58 09-02-10
TABLE 2
Id | final | Date
------------------
1 330 02-11-14
2 5 07-01-12
3 100 09-02-10
ADD both Table 1 and Table 2 Sum'd values(column final), and then work out the AVG number from this and create this as another column average, THEN if table2 for example SUM'd original amount (before the AVG) is higher than Table 1 SUM'd amount create another column and print in that column 'Tbl2 has the higher amount' and vise verser if table 1 had the higher amount.
End result Column wise table would look like this :
|tb1_final_amount|tb2_final_amount|Avg_Amount|Top_Score_tbl
|tb1_final_amount|tb2_final_amount|Avg_Amount|Top_Score_tbl
304 435 369.5 tb2 has highest score

Answer 1

This is one way (of many) to do this. You can sum up the two tables and use them as derived tables in a query like so:
select
tb1_final_amount,
tb2_final_amount,
(tb1_final_amount+tb2_final_amount)/2.0 as Avg_Amount,
case
when tb1_final_amount < tb2_final_amount then 'tb2 has highest score'
else 'tb1 has highest score'
end as Top_Score_tbl
from
(select SUM(final) as tb1_final_amount from TABLE1) t1,
(select SUM(final) as tb2_final_amount from TABLE2) t2

Answer 2

This does the trick!:
--SET UP Table1
CREATE TABLE Table1 (ID INT, final INT, [Date] DATETIME)
INSERT Table1 VALUES (1, 236, '20141102')
INSERT Table1 VALUES (2, 10, '20120107')
INSERT Table1 VALUES (3, 58, '20100209')
--SET UP Table2
CREATE TABLE Table2 (ID INT, final INT, [Date] DATETIME)
INSERT Table2 VALUES (1, 330, '20141102')
INSERT Table2 VALUES (2, 5, '20120107')
INSERT Table2 VALUES (3, 100, '20100209')
-- Query
SELECT
SUM(CASE WHEN t.TableName = 'Table1' THEN T.final
ELSE 0
END) AS tb1_final_amount,
SUM(CASE WHEN t.TableName = 'Table2' THEN T.final
ELSE 0
END) AS tb2_final_amount,
AVG(T.final) AS Avg_Amount,
ISNULL((
SELECT
'Table1'
FROM
Table1 T1
WHERE
SUM(CASE WHEN t.TableName = 'Table1' THEN T.final
ELSE 0
END) > SUM(CASE WHEN t.TableName = 'Table2' THEN T.final
ELSE 0
END)
), 'Table2')
FROM
(
SELECT
'Table1' AS TableName,
final
FROM
Table1
UNION ALL
SELECT
'Table2',
final
FROM
Table2
) AS T