Statistics in Oracle: DBMS_UTILITY

With DBMS_UTILITY.ANALYZE_SCHEMA you can gather all the statistics for all the tables, clusters and indexes of a schema.
Code examples
exec DBMS_UTILITY.ANALYZE_SCHEMA('SCOTT','COMPUTE');
exec DBMS_UTILITY.ANALYZE_SCHEMA('SCOTT','ESTIMATE', estimate_rows =>
1000);
exec DBMS_UTILITY.ANALYZE_SCHEMA('SCOTT','ESTIMATE', estimate_percent
=> 25);
exec DBMS_UTILITY.ANALYZE_SCHEMA('SCOTT','DELETE');
Note: It's also possible to analyze the whole database with the DBMS_UTILITY.ANALYZE_DATABASE('COMPUTE'); command.