How to shrink datafiles, when you need to rebuild tables/indexes, or move LOBs around

 Below are 2 links with very good explanations, thanks to Jonathan Lewis!!!

https://jonathanlewis.wordpress.com/tablespace-hwm/

https://jonathanlewis.wordpress.com/2010/02/06/shrink-tablespace/

These help when you get:

ORA-03297: file contains used data beyond requested RESIZE value

but there is a lot of free space in the datafile, just not compacted.