I'm new to Oracle spatial and finding it hard to visualize complex Aggregate Geometry functions. So are there any provisions in Toad for Oracle to view the results of the queries on spatial data?
TOAD doesn't support any kind of visualisation for the geometry data type, but there is one built into SQL Developer, which you can get for free from Oracle.
You can find out more information here: http://beyond-just-data.blogspot.co.uk/2015/07/sqldeveloper-and-map-data.html