We can override the SQL’s for relational data base source in a design job using “Override command” available under “Dataflow Transforms” of design job.

Click on the arrow provided beside the source transform to view all the SQL’s for a design job.

We can modify the query as needed and save the changes. After saving, we can find a revert symbol.

Whenever we want to revert the changes we have done, we can just click on the revert symbol, which replaces our queries to the original ones.