Top 'N' analysis : Filter View « View « Oracle PL/SQL Tutorial






SQL>
SQL>
SQL> CREATE TABLE product (
  2       product_name     VARCHAR2(25) PRIMARY KEY,
  3       product_price    NUMBER(4,2),
  4       quantity_on_hand NUMBER(5,0),
  5       last_stock_date  DATE
  6       );

Table created.

SQL>
SQL> INSERT INTO product VALUES ('Product 1', 99,  1,    '15-JAN-03');

1 row created.

SQL> INSERT INTO product VALUES ('Product 2', 75,  1000, '15-JAN-02');

1 row created.

SQL> INSERT INTO product VALUES ('Product 3', 50,  100,  '15-JAN-03');

1 row created.

SQL> INSERT INTO product VALUES ('Product 4', 25,  10000, null);

1 row created.

SQL> INSERT INTO product VALUES ('Product 5', 9.95,1234, '15-JAN-04');

1 row created.

SQL> INSERT INTO product VALUES ('Product 6', 45,  1,    TO_DATE('December 31, 2008, 11:30 P.M.','Month dd, YYYY, HH:MI P.M.'));

1 row created.

SQL>
SQL>
SQL>
SQL> CREATE OR REPLACE VIEW overstocked_items AS
  2  SELECT product_name, quantity_on_hand
  3  FROM   product
  4  WHERE  rownum <= 3
  5  ORDER BY quantity_on_hand;

View created.

SQL>
SQL>
SQL> SELECT * FROM overstocked_items;

PRODUCT_NAME              QUANTITY_ON_HAND
------------------------- ----------------
Product 1                                1
Product 3                              100
Product 2                             1000

SQL>
SQL>
SQL> drop table product;

Table dropped.

SQL>
SQL> drop view overstocked_items;

View dropped.

SQL>








8.8.Filter View
8.8.1.Create a view with condition
8.8.2.Creating a simple filtering view
8.8.3.Creating a view that joins tables
8.8.4.Top 'N' analysis
8.8.5.Query a filtering view
8.8.6.Create a view for employee and its course during
8.8.7.Use view to simplify the query
8.8.8.Create a view to link two table together
8.8.9.Use view to wrap complex select statement