11.创建视图

Refer back to the queries
in [Section 2.6]{.ul}.
Suppose the combined listing of weather records and city location is of
particular interest to your application, but you do not want to type the
query each time you need it. You can create a view over the query,
which gives a name to the query that you can refer to like an ordinary
table:

CREATE VIEW myview AS

SELECT city, temp_lo, temp_hi, prcp, date, location

FROM weather, cities

WHERE city = name;

SELECT * FROM myview;

Making liberal use of views is a key aspect of good SQL database design.
Views allow you to encapsulate the details of the structure of your
tables, which might change as your application evolves, behind
consistent interfaces.

Views can be used in almost any place a real table can be used. Building
views upon other views is not uncommon.