What does the SQL standard say about parentheses in SQL UNION/EXCEPT/INTERSECT statements?

Question

I\'m trying to write a SQL UNION that works on both MySQL and SQLite.

(select_clause_A) UNION (select_clause_B)

SQLite doesn\'t like the pa

Answer 1

The parens should not be required for MySQL, and from what I can tell reading the spec are not supposed to be there.

MySQL is also nonstandard in that it supports an ORDER BY in each "part" of the union, so if you're writing it for non-MySQL you can't do that anyway.