Sorting Rows

You can order the rows in a query result.  That is, you can name a particular column or set of columns whose values determine the order of rows in the result set.  There are several ways in which you can use ordering:

• You can arrange rows in ascending or descending order   By default, SQL uses order-by columns to arrangesrows in ascending order.  For example, to arrange the book titles by ascending price, simply sort the rows by the price column.  The resulting SQL might look like this:

  SELECT *
  FROM titles
  ORDER BY price
  

  On the other hand, if you want to arrange the titles with the more expensive books first, you can explicitly specify a highest-first ordering.  That is, you indicate that the result rows should be arranged by descending values of the price column.  The resulting SQL might look like this:

  SELECT *
  FROM titles
  ORDER BY price DESC
  

• You can sort by multiple columns   For example, you can create a result set with one row for each author, ordering first by state and then by city.  The resulting SQL might look like this:

  SELECT *
  FROM authors 
  ORDER BY state, city
  

• You can sort by columns not appearing in the result set   For example, you can create a result set with the most expensive titles first, even though the prices do not appear.  The resulting SQL might look like this:

  SELECT title_id, title
  FROM titles
  ORDER BY price DESC
  

• You can sort by derived columns   For example, you can create a result set in which each row contains a book title — with the books that pay the highest royalty per copy appearing first.  The resulting SQL might look like this:

  SELECT title, price * royalty / 100 as royalty_per_unit
  FROM titles
  ORDER BY royalty_per_unit DESC
  

  (The formula for calculating the royalty that each book earns per copy is emphasized.) 

  To calculate a derived column, you can use SQL syntax, as in the preceding example, or you can use a user-defined function that returns a scalar value.  For more information about user-defined functions, see User-Defined Functions.
  

• You can sort grouped rows   For example, you can create a result set in which each row describes a city, plus the number of authors in that city — with the cities containing many authors appearing first.  The resulting SQL might look like this:

  SELECT city, state, COUNT(*)
  FROM authors
  GROUP BY city, state
  ORDER BY COUNT(*) DESC, state 
  

  (Notice that the query uses state as a secondary sort column.  Thus, if two states have the same number of authors, those states will appear in alphabetical order.)
  

• You can sort using international data   That is, you can sort a column using collating conventions that differ from the default conventions for that column.  For example, you can write a query that retrieves all the book titles by the Icelandic novelist Halldor Laxness.  To display the titles in alphabetical order, you use an Icelandic collating sequence for the title column.  The resulting SQL might look like this:

  SELECT title
  FROM 
      authors 
      INNER JOIN 
          titleauthor 
          ON authors.au_id 
          =  titleauthor.au_id 
          INNER JOIN
              titles 
              ON titleauthor.title_id 
              =  titles.title_id 
  WHERE 
       au_fname = 'Halldor' AND 
       au_lname = 'Laxness'
  ORDER BY 
       title COLLATE SQL_Icelandic_Pref_CP1_CI_AS

For more information about sorting result rows, see Ordering Query Results.