PLease, read my comment to the question.
Try this:
INSERT INTO Course_Data (Branch,CC,C_Title,Sem,Credits)
SELECT DISTINCT Branch,CC,C_Title,Sem,Credits
FROM (
SELECT Branch,CC,C_Title,Sem,Credits
FROM Course_Data
UNION ALL
SELECT Branch,CC,C_Title,Sem,Credits
FROM TEMP1
) AS A
ORDER BY A.CC)
For further information, please see:
INSERT (SQL)[
^]