Sql to find database,redo and temp size

select (select sum(bytes/1048576) from dba_data_files) “Data Mb”,
(select NVL(sum(bytes/1048576),0) from dba_temp_files) “Temp Mb”,
(select sum(bytes/1048576)*max(members) from v$log) “Redo Mb”,  3
(select sum(bytes/1048576) from dba_data_files) +
(select NVL(sum(bytes/1048576),0) from dba_temp_files) +
(select sum(bytes/1048576)*max(members) from v$log) “Total Mb”
from dual;