Get data from both tables what join should I use I have T1 as table 1 

----------------
field1 | field2
---------------
 val1  | val2


I have T2 as table 2 

----------------
field1 | field2
---------------
 val11  | val22


I want to write a query which can produce result like this 

 field1 | field2 | T1.T2 | 
 ------------------------|
 val11  | val22  | T2    | 
 val1   | val2   | T1    |
Simply, you can use a CTE or SubQuery then ORDER BY [T1.T2] DESC as

WITH CTE AS
(
  SELECT Col1, Col2, 'T1' [T1.T2]
  FROM T1
  UNION
  SELECT Col1, Col2, 'T2'
  FROM T2
)
SELECT *
FROM CTE
ORDER BY [T1.T2] DESC;


Live Demo