How to identify the SQL consuming more resources in Oracle?

Problem:

You want to identify the SQL statements consuming more resources in Oracle.

Solution

“V$SQLSTATS" view displays performance statistics for SQL statements that have recently executed. You can also use "V$SQL” and “V$SQLAREA" to report on SQL resource usage. 

"V$SQLSTATS” is faster and retains information for a longer period of time, but contains only a subset of the columns in “V$SQL" and "V$SQLAREA”.

Example

select * from(
select
  sql_text
 ,buffer_gets
 ,disk_reads
 ,sorts
 ,cpu_time/1000000 cpu_sec
 ,executions
 ,rows_processed
from v$sqlstats
order by cpu_time DESC)
where rownum < 20;