SELECT store.name, sum (sale_amount) AS sales_sum
FROM store, sales, date, product
WHERE product.name 'Portable DVD Player' AND
product.id sales.product_id AND
sales.store_id store.id AND
sales.date date.date AND
GROUP BY store.id
ORDER BY sales_sum
Figure 1-1 shows four tables: SALES, PRODUCT, STORE, and
DATE. The SALES table contains the sales amount and keys into the
other three tables, indicating the product sold, the store that sold it,
and the date that it was sold. The PRODUCT table provides the name
of the product as well as a hierarchical grouping of that product into
higher-level categories. A product belongs to a particular group,
which belongs to a more general category (e.g., Coca-Cola 20-ounce
soda may have a product group of “colas” and be in the product
category of “soft drinks”).
Another technology to distinguish from data mining is Online
Analytical Processing (OLAP) technology [Wikipedia-OLAP 2006].
OLAP supports summaries, forecasts, and trend analysis. For example,
summaries often involve “rolling up” data to different levels of
granularity as defined by a dimension, such as Date, which can
Example of a star schema.