So they both store data in a table like structure, but that’s about where the similarities end. Excel is useful for handling smaller more flexible data sets, but has performance, scalibility, storage, and structural deficiencies compared to SQL, it’s also harder for computer languages to communicate with a shared excel dataset and modify it vs SQL.

One of the major issues with excel as a database is data limits, excel only allows for ~1 million rows. Considering there are ~1 billion possible SSNs, excel would not be a great medium for them for that reason alone.

One big advantage of SQL is you need to structure your data on the creation of the table and it’s designed with the expectation that all data will fit a structure, including unique keys, format, and other limits and structures. This allows you to enforce database rules easily and massively reduce storage size and query times.

There are a bunch of other reasons for using SQL but most of it boils down to either it’s faster, easier for multiple computers to access and read/modify simultaneously, or better for enforcing rules and structures when modifying it.