Oracle column operations (add columns, modify columns, delete columns)

1. Add a column:

Alter table name add column name varchar2 (10);

2. Modify a column:

　　Alter Table name modify column name varchar2 (20);

3. Delete a column:

　　Alter table name drop column name ;

Here are a few places to note, first, add and modify the column is not required to add the keyword column, or will error ora-00905.

Second, to delete a single column, be sure to add column, and then remember that the deletion is not required to add the type.

4. Add multiple columns:

　　Alter table name Add ( column name 1 varchar2 (Ten), column name 2 number);

5. Modify multiple columns:

　　Alter Table name Modify ( column name 1 varchar2, column name 2 varchar2 (20));

6. Delete multiple columns:

　　Alter table name drop ( column name 1, column name 2);

Strange phenomenon, in the column to add the keyword column, however, when you delete multiple columns, you cannot add the column keyword.

Oracle column operations (add columns, modify columns, delete columns)