Some databases like ArangoDB (https://www.arangodb.com/) allow you to use Javascript instead of SQL.
However, using a type-unsafe (read weak typing), turing-complete language introduces the usual problems we know and love, such as infinite loops, runtime type errors, exceptions, and the like.
Personally, I'm looking forward to a WASM runtime for databases -- so we can run webassembly on the database. This COULD be carefully designed to be statically checked and, possibly, make it really hard to write runaway loops.
Many databases support other languages as well (eg. PostgreSQL supports many including Python, by default). One challenge is lack of standardization. (SQL is a weak standard, but at least a standard).
Weak typing: what about TypeScript?
Slow loops: yes, this is a problem. However, SQL (and even more so, GraphQL) also has a problem of large results / operations spanning too many entries. During development, the number of entries is fine, but not in production. Specially if indexes are missing, this is also a problem in SQL. (Endless loops are actually less of a problem than slow loops: it's easier to detect endless loops during development).
To process large results in a good way, often, pagination is needed; best would be keyset pagination. What if a statement returns a "continuation" statement in addition to the result set? If the client wants to get more results (or process more entries), then he would need to run the "continuation" statement.
Say a database doesn't provide SQL, but instead a set of low-level APIs (plus a ton of tools). Developers would then (be forced to) write properly modularized, versioned code on top of those APIs.
However, using a type-unsafe (read weak typing), turing-complete language introduces the usual problems we know and love, such as infinite loops, runtime type errors, exceptions, and the like.
Personally, I'm looking forward to a WASM runtime for databases -- so we can run webassembly on the database. This COULD be carefully designed to be statically checked and, possibly, make it really hard to write runaway loops.