What are the different methods for creating views in Oracle?

There are several methods for creating views in Oracle.

1. The CREATE VIEW statement is used to create a view. The syntax is as follows:
   CREATE VIEW view_name AS
   SELECT column1, column2, …
   FROM table_name
   WHERE condition;
2. By using the CREATE OR REPLACE VIEW statement, you can create or replace an existing view. If the view already exists, it will be replaced. If the view does not exist, it will be created. The syntax is as follows:
   CREATE OR REPLACE VIEW view_name AS
   SELECT column1, column2, …
   FROM table_name
   WHERE condition;
3. To create a materialized view using the CREATE MATERIALIZED VIEW statement, you can create a table that stores the results of a query. The syntax is as follows:
   CREATE MATERIALIZED VIEW view_name
   BUILD IMMEDIATE
   REFRESH COMPLETE
   START WITH SYSDATE
   NEXT SYSDATE + 1
   AS
   SELECT column1, column2, …
   FROM table_name
   WHERE condition;
4. Create a view using a WITH clause: You can create a temporary view using a WITH clause, which will only be visible in the current query. The syntax is as follows:
   WITH view_name AS
   (SELECT column1, column2, …
   FROM table_name
   WHERE condition)
   SELECT *
   FROM view_name;

These are commonly used methods for creating views, choose the method that best suits your needs.