SQLite Forum

When is SELECT ... FROM with no table-or-subquery valid.
I sincerely hope NOT. It has been perfectly legal (right up to release 3.24) to do 

SELECT 1,datetime(...),trim(...);

Since there is no FROM clause, the SELECT-list is limited to expressions that do not reference any table.

BTW: Oracle does not allow an empty FROM clause, so they provide an empty table named DUAL that exists solely to fulfill an otherwise empty FROM clause.