it would also be able to suggest columns/fields from your database, as well as picking up errors. for example, given this table:

    create table profiles (
      id serial primary key,
      first_name text,
      last_name text
    );

and this query:

    select id, firstname from profiles;

it would then help to detect if you had an error in your select query (in this case, "firstname" should be "first_name"), and your code editor would show a warning, even before you try to run the code inside your database

Essentially, LSPs are generic implementations of features like autocomplete, expand selection, refactor, etc., with a standardized API.

Different editors and IDEs can use the same LSP, without the need to reinvent/reimplement the wheel.