Reading a recent answer it became apparent that the SQL that is accepted in a DDL query (Tools->SQL) depends on the db engine and on the version of that engine. Obvs when you think of it!
So my new question is whether there is a command that can be put into Tools->SQL that will tell me what the embedded db is, and what it is currently running. Presumably this is HSQLDB-dependent at present (and from LO 6.1 will depend on the forthcoming embedded db which is Firebird)