Delete Based on Another Table

I recently had to delete records in one table based on the data in another table. This isn't particularly tricky, but the only examples I could find online ended up deleting all the records in the table.

The code at the beginning is just to set up a table I can use as an example.

Conn Scott/Tiger
Set Feedback On Echo On

Select *
From Dept;

Drop Table Dept2 Purge;

Create Table Dept2 As
Select * From Dept;

Insert Into Dept2 Values(50,'HR','PITTSBURGH');
Insert Into Dept2 Values(60,'HOUSEKEEPING','LA');
Insert Into Dept2 Values(70,'MANAGEMENT','ATLANTA');

Select * From Dept2;

This code deletes from the newly created table where a record exists in the original table that has a matching key.

Delete From Dept2
 Where Exists
          (Select 1
             From Dept
            Where Dept.Deptno = Dept2.Deptno);

Select * From Dept2;

Timestamp in an External Table

Since this wasn't particularly easy to find, and it took several tries, I decided to post it here. As most things, once you know how to write it, it's not particularly tricky.

Input Data from External Table:
1,Jan 8 1998 12:43:27:012AM
2,Feb 19 1998 2:43:27:111PM
3,Jan 8 2008 3:49:27:693PM

Create Table Ext_Dt
(  Item       Number
 , Needed_By  Timestamp
)
Organization External
(
 Type Oracle_Loader
 Default Directory Ext
 Access Parameters
 (
    Records Delimited By Newline
    Badfile 'Date.Bad'
    Logfile 'Date.Log'
    Fields Terminated By ','
    Missing Field Values Are Null
       (
          Item,
          Needed_By Char Date_Format Timestamp Mask 'Mon Dd Yyyy Hh:Mi:Ss:Ff3am'
       )
 )
Location (Ext:'Dt.Txt')
)
Reject Limit Unlimited;

Select Item
     , Needed_By
     , To_Char(Needed_By,'Mon' ) Mth
     , To_Char(Needed_By,'Hh24') Hr
  From Ext_Dt;