24年一季度版本支持DBA_IND_EXPRESSIONS视图；
之前版本可以尝试用dba_ind_columns、sysobjects、sysindexes视图关联查询看看是否能满足需求

select a.index_owner,a.index_name,a.table_owner,a.table_name,
--utl_raw.cast_to_varchar2(c.keyinfo) as column_expression,
indexdef(c.id,1),
a.column_position
from dba_ind_columns a
inner join sysobjects b on a.index_name=b.name
inner join sysindexes c on b.id=c.id
where c.xtype=3;