How To Delete a Column in an Existing Table?
If you have an existing column in a table and you need that column any more, you can delete it with ALTER TABLE … DROP COLUMN statement. Here is an example SQL script: SQL> CREATE TABLE emp_dept_90 2 AS SELECT * FROM employees WHERE department_id=90; Table created. SQL> SELECT last_name FROM emp_dept_90; LAST_NAME ————————- King Kochhar De Haan SQL> ALTER TABLE emp_dept_90 DROP COLUMN last_name; Table altered. SQL> SELECT last_name FROM emp_dept_90; ERROR at line 1: ORA-00904: “LAST_NAME”: invalid identifier As you can see the column “last_name” is gone.