Is NATURAL (JOIN) considered harmful in production environment?

Question

I am reading about NATURAL shorthand form for SQL joins and I see some traps:

• it just takes automatically all same named column-pairs (use USING to specify explicit column list)
• if some new column is added, then join output can be "unexpectedly" changed too, which may be not so obvious (even if you know how NATURAL works) in complicated structures

Answer 1

NATURAL JOIN syntax is anti-pattern:

• The purpose of the query is less obvious;
  • the columns used by the application is not clear
  • the columns used can change "unexpectedly"
• The syntax goes against the modularity rule, about using strict typing whenever possible. Explicit is almost universally better.

Because of this, I don't recommend the syntax in any environment.
I also don't recommend mixing syntax (IE: using both NATURAL JOIN and explicit INNER/OUTER JOIN syntax) - keep a consistent codebase format.