Developers can select rows from a View. For example, suppose the database includes a view called “LargeLCD,” in which each row describes a PC monitor which diagonal exceed 19 inches. The view definition might look like this:
SELECT *
FROM monitors
WHERE diagonal > 21
Developers can select the expensive monitors merely by selecting the expensive monitors from the LargeLCD view. The resulting SQL might look like this:
SELECT *
FROM LargeLCD
WHERE price > 400
Similarly, a view can participate in a JOIN operation. For example, developers can find the sales of large monitors merely by joining the sales table to the LargeLCD view. The resulting SQL might look like this:
SELECT *
FROM sales
INNER JOIN
LargeLCD
ON sales.model_id
= LargeLCD.model_id