September 2017 Update

Task/Date-manipulation/SQL/date-manipulation.sql

@@ -0,0 +1,32 @@
+-- March 7 2009 7:30pm EST
+
+select
+TO_TIMESTAMP_TZ(
+'March 7 2009 7:30pm EST',
+'MONTH DD YYYY HH:MIAM TZR'
+)
+at time zone 'US/Eastern' orig_dt_time
+from dual;
+
+-- 12 hours later DST change
+
+select
+(TO_TIMESTAMP_TZ(
+'March 7 2009 7:30pm EST',
+'MONTH DD YYYY HH:MIAM TZR'
+)+
+INTERVAL '12' HOUR)
+at time zone 'US/Eastern' plus_12_dst
+from dual;
+
+-- 12 hours later no DST change
+-- Arizona time, always MST
+
+select
+(TO_TIMESTAMP_TZ(
+'March 7 2009 7:30pm EST',
+'MONTH DD YYYY HH:MIAM TZR'
+)+
+INTERVAL '12' HOUR)
+at time zone 'US/Arizona' plus_12_nodst
+from dual;