You can write loops in (the procedural extensions of) SQL, but IME it's very rare that you'd want to. The bigger issue is the lack of performant abstractions -

You can write loops in (the procedural extensions of) SQL, but IME it's very rare that you'd want to. The bigger issue is the lack of performant abstractions - I copy-paste orders of magnitude more code in SQL than in any other language I've used. There are basically just views and functions, and both can carry substantial (read: multiple orders of magnitude) performance penalties compared to the copy-paste approach, especially when you try to nest or compose them. Materialized views rectify this somewhat but they come with various RDBMS-specific limitations and gotchas.