Is there a oracle SQL query show me how many time I had Downtime in my Database through a year?
Example for Oracle 11.2

Prepare

sqlplus / as sysdba 
CREATE VIEW X$_DBGALERTEXT AS SELECT * FROM X$DBGALERTEXT; 
GRANT SELECT ON X$_DBGALERTEXT TO &lt;USERNAME&gt;; 
CREATE SYNONYM &lt;USERNAME&gt;.X$DBGALERTEXT FOR SYS.X$_DBGALERTEXT;


select startup and shutdown time database.

select  to_char(originating_timestamp, 'YYYY-MM-DD HH24:MI' ), message_text 
from X$DBGALERTEXT
where  message_text like '%Starting ORACLE instance%' or
       message_text like '%Instance shutdown%'


Example output 

2018-07-31 10:45    Starting ORACLE instance (normal)

2018-07-31 11:12    Instance shutdown complete

2018-07-31 11:13    Starting ORACLE instance (normal)

2019-01-25 10:16    Instance shutdown complete

2019-01-25 14:15    Starting ORACLE instance (normal)