Ordering and Grouping
The results from a
SELECT are, by default, indeterminate in the order
they will appear. Fortunately, SQL provides some tools for imposing
discipline on this seemingly random list: ordering and grouping.
You can tell a database to order any results you see by a certain
column. For example, if you specify that a query should order the
last_name, then the results will appear
alphabetized according to the
Ordering is handled by the
SELECT last_name, first_name, age FROM people ORDER BY last_name, first_name
In this situation, we are ordering by two
columns. You can order by any number of
columns. You can also use the special
) clause to return results in a random order.
If you want to see things in reverse order, add the
ORDER BY last_name DESC
DESC keyword applies only to the field that
comes directly before it. If you are sorting on multiple fields, only
the field directly before
DESC is reversed; the
others are sorted in ascending order.
Sorting is actually a complex problem for applications that need to run on computers all over the world. The rules for sorting strings vary from alphabet to alphabet, even when two alphabets use mostly the same symbols. MySQL handles the problem of sorting by making it dependent on the character set used by the MySQL engine. Out of the box, the default character set is ISO-8859-1 (Latin-1). MySQL uses the ...