Computer Programming Concepts and Visual Basic David I. Schneider

question mark stands for a single character in the same position as the question mark. For
instance, the pattern “B?d” is matched by “Bid”, “Bud”, and “Bad”. An asterisk stands for
any number of characters in the same position as the asterisk. For instance, the pattern “C*r”
is matched by “Computer”, “Chair”, and “Car”. See Comments 3 through 5 for further information
about Like.
In the sentence
SELECT fields FROM clause
fields is either * (to indicate all fields) or a sequence of the fields to be available (separated
by commas), and clause is either a single table or a join of two tables. A join of two tables is
indicated by a clause of the form
table1 INNER JOIN table2 ON foreign key of table1=primary key of table2
Appending
WHERE criteria
to the end of the sentence restricts the records to those satisfying criteria. Appending
ORDER BY field(s) ASC (or DESC)
presents the records ordered by the specified field or fields.
In general, the SQL statements we consider will look like
SELECT www FROM xxx WHERE yyy ORDER BY zzz
where SELECT www FROM xxx is always present and accompanied by one or both of WHERE
yyy and ORDER BY zzz. In addition, the xxx portion might contain an INNER JOIN phrase.
The settings for the examples mentioned earlier are as follows:
I (a) Show the records from Cities in alphabetical order based on the name of the city.
SELECT * FROM Cities ORDER BY city ASC
I (b) Show the records from Cities in alphabetical order based first on the name of the
country and,, within each country group,, the name of the city.
SELECT * FROM Cities ORDER BY country,, city ASC
I (c) Show the records from Cities in descending order based on the projected 2015
population.
SELECT * FROM Cities ORDER BY pop2015 DESC
II (a) Show the records for the Cities in China.
SELECT * FROM Cities WHERE country = ‘China’
II (b) Show the records from Cities whose 2015 population is projected to be at least 20
million.
SELECT * FROM Cities WHERE pop2015 >= 20
II (c) Show the records from Cities whose name begins with the letter S.
SELECT * FROM Cities WHERE city Like ‘S*’
III (a) Show the records from the joined table in descending order of the populations of
their countries.
SELECT * FROM Cities INNER JOIN Countries ON Cities.country =
Countries.country ORDER BY Countries.pop1995 DESC
Relational Databases and SQL 333