For increased complexity, SQL actually has two kinds of keywords, reserved and non-reserved, non-reserved is what some grammars call contextual or lexical keywo

For increased complexity, SQL actually has two kinds of keywords, reserved and non-reserved, non-reserved is what some grammars call contextual or lexical keywords: they are only keywords in specific contexts, but are generally usable as unquoted identifiers. And obviously this is only for maximally portable SQL, postgres has a comparative table, which demonstrates that many of SQL's reserved keywords are non-reserved in postgres-sql: https://www.postgresql.org/docs/current/sql-keywords-appendix.html https://www.postgresql.org/docs/current/sql-keywords-appendi...