Oracle insert, merge, query, and aggregate operations

Oracle inserts query data from one table into another table

Insert   Into T_idd_event_history (detectorcode, detectorname, loopcode, subeventtype, description, occuretime, releasetime)
Select T. detectorid, T. detectorname, T. loopcode, T. subeventtype, T. Description, T. updatetime, sysdate From T_iid_event_current t

Oracle SQL date comparison:
Before today:

Select   *   From Up_date Where   Update   < To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )
Select   *   From Up_date Where   Update   <= To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )

After today:

Select   *   From Up_date Where   Update   > To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )
Select   *   From Up_date Where   Update   > = To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )

Exact time:

Select   *   From Up_date Where   Update   = To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )

In a certain period of time:

Select   *   From Up_date Where   Update   Between To_date ( ' 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' ) And To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )
Select   *   From Up_date Where   Update   < To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' ) And   Update   > To_date ( ' 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )
Select   *   From Up_date Where   Update   <= To_date ( ' 2007-09-07 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' ) And   Update   > = To_date ( ' 00:00:00 ' , ' Yyyy-mm-dd hh24: MI: SS ' )