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SQL Anywhere 11.0.1 (Français) » SQL Anywhere Server - SQL Usage » Querying and Modifying Data » Querying data


The ORDER BY clause: Ordering results

Unless otherwise requested, the database server returns the rows of a table in an order that has no meaning. Often it is useful to look at the rows in a table in a more meaningful sequence. For example, you might like to see products in alphabetical order.

You order the rows in a result set by adding an ORDER BY clause to the end of the SELECT statement. This SELECT statement has the following syntax:

SELECT column-name-1, column-name-2,...
FROM table-name
ORDER BY order-by-column-name

You must replace column-name-1, column-name-2, and table-name with the names of the columns and table you are querying, and order-by-column-name with a column in the table. As before, you can use the asterisk as a short form for all the columns in the table.

♦  List the products in alphabetical order
  • The order of clauses is important   The ORDER BY clause must follow the FROM clause and the SELECT clause.

  • You can specify either ascending or descending order   The default order is ascending. You can specify a descending order by adding the keyword DESC to the end of the clause, as in the following query:
    SELECT ID, Quantity
       FROM Products
       ORDER BY Quantity DESC;

    ID Quantity
    400 112
    700 80
    302 75
    301 54
    600 39
    ... ...

  • You can order by several columns   The following query sorts first by size (alphabetically), and then by name:
    SELECT ID, Name, Size
       FROM Products
       ORDER BY Size, Name;

    ID Name Size
    600 Sweatshirt Large
    601 Sweatshirt Large
    700 Shorts Medium
    301 Tee Shirt Medium
    ... ... ...

  • The ORDER BY column does not need to be in the select list   The following query sorts products by unit price, even though the price is not included in the result set
    SELECT ID, Name, Size
       FROM Products
       ORDER BY UnitPrice;

    ID Name Size
    500 Visor One size fits all
    501 Visor One size fits all
    300 Tee Shirt Small
    400 Baseball Cap One size fits all
    ... ... ...

  • If you do not use an ORDER BY clause, and you execute a query more than once, you may appear to get different results   This is because SQL Anywhere may return the same result set in a different order. In the absence of an ORDER BY clause, SQL Anywhere returns rows in whatever order is most efficient. This means the appearance of result sets may vary depending on when you last accessed the row and other factors. The only way to ensure that rows are returned in a particular order is to use ORDER BY.

Using indexes to improve ORDER BY performance