Hello everyone,
Please I downloaded a dataset in excel format from BankFocus' website for 1455 banks within 19 EU countries and used it to estimate competition using Lerner index and Boone indicator and I've saved the result (Lerner and Boone) in dta format.

Moreover, I have another dataset (macroeconomic data) in excel format from world bank's website for the same 19 EU countries but there are no banks or firms attached to this new dataset.

Now I want to merge or join these two datasets to help me estimate the impact of the competition measures (Lerner and Boone) on one of the macroeconomic variables (GDP) using regression. So how do I merge or combine or join these two datasets?

Or differently put, how do I add the competition measures (Lerner and Boone) to the macroeconomic dataset? Which stata function can help me to merge these two datasets?
I would be grateful for your assistance, thanks.