how to merge old data and new data in sql table

See more:

SQL

server

hi everyone i have a question on how to merge old data and new data with dropping or duplicating table in sql? wherein how i will do that?? can you help me or give me a good link resource for this? thanks

for example: i have upload data in my table then i update all data file on the existing data yet it expect to upload again same data but same with the 1st data uploaded since it is already updated it will not change at the same time yet it will not also duplicated in the sql data table source in my database..wherein im experiencing the existing data with new and old data is updating BUT i can make it to merge it to the data table in sql..so please help me..


thanks in advance