Puede usar una hierarchical query sin JOIN condición :
select t1.*, level as line_num,
regexp_replace( regexp_substr( t1.f_content,'[^~]+', 1, level), '(^[[:space:]]+)' )
as line
from table1 t1
connect by level <= regexp_count(f_content, '~')
and prior f_name = f_name
and prior sys_guid() is not null
