JAVA J2EE 4 U

 SELECT 

    ROUND(SUM(CASE WHEN status = 'A' THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2) AS backup_success_pct,

    COUNT(*) AS total_backups,

    SUM(CASE WHEN status = 'A' THEN 1 ELSE 0 END) AS successful_backups,

    SYSDATE AS report_time

FROM 

    v$backup_piece;