Well, some of this is sinking in finally today.

I now understand that what was meant about relating the a and b tables.
Code:
FROM T215 a,
	 FIELD_ENUM_VALUES enumval, 
	 (SELECT c1,TO_CHAR(TO_DATE('01-JAN-1970','DD-MON-YYYY') + c6/86400
	   ,'MM-DD-YYYY') mod_date FROM T215) b
WHERE enumval.schemaid = 215
	   AND   enumval.fieldid = 7
	   AND   enumval.enumid = a.c7
	   AND		 a.c1 = b.c1
I'm still working on this thing, and I still welcome any and all suggestions.
Mark