Try this applet to draw your own syntactic
diagrams (java 1.1).
button << : go to the precedent rule.
button <in: to load a grammar from input window (errors are report in debug window)
clic on non-terminal: to explore the grammar.
at the begining the grammar is SQL as implemented by Oracle(tm) DBMS version 7.
(There exist some problems with the Java VM from Netscape on Macintosh! so ...)