You need tests either way. It's hard to write a test that checks behavior but misses a wrong-type. Simply running the problematic code will most likely throw an exception.
The type deduction is not so automatic in most languages, TS included. Rust has the most automatic one I've seen, and of course that kind of language needs static typing. But still, it's more explicit than needed for a typical web backend.
SQL type autogen is limited to full rows, so any query returning an aggregate or something isn't going to work with that. Even for full rows, it's eh. Usually I just see that encouraging people to do local computations that should be in SQL.
The type deduction is not so automatic in most languages, TS included. Rust has the most automatic one I've seen, and of course that kind of language needs static typing. But still, it's more explicit than needed for a typical web backend.
SQL type autogen is limited to full rows, so any query returning an aggregate or something isn't going to work with that. Even for full rows, it's eh. Usually I just see that encouraging people to do local computations that should be in SQL.