SQL ORDER BY.

ORDER BY in the SELECT Statement.

• ORDER BY is used for sorting the query results.
  ORDER BY Syntax within the SELECT statement:

  SELECT  select_list
    FROM table/view_list
    [WHERE search_conditions]
    [ORDER BY order_by_list ]

• Most (but not all) systems RDBMS require that each item in the ORDER BY order_by_list also appears in the SELECT column_list.
• ORDER BY can handle four types of expression in the sort:
  1. A column name.
  2. A column name including arithmetic operators or functions (price * 1.0825).
  3. A display label assigned to a column or expression in the SELECT clause.
  4. Column position numbers in the column list of a SELECT statement.
  Each expression in an ORDER BY can also be specified with:

  DESC	Means; in DESCending order
  ASC	Means; in ASCending order (default)

  Example using 2. and 3. Expression type:

  MySQL, Oracle, SQL server, PostgreSQL:

  select ISBN_no "ISBN", item_qty*PRICE "Order Sum" 
    from order_books
    where Isbn_no like '%8'
    OR Isbn_no like '0%'
    AND item_qty*PRICE < 100 
    ORDER BY ISBN_NO , item_qty*PRICE DESC;

  The result should be:

  ISBN	Order Sum
  0201703092	78
  0471777781	64
  0672325764	49
  0764557599	84
  0764557599	42
  0764579088	140

  Example using 1. and 4. Expression type:

  MySQL, Oracle, SQL server, PostgreSQL:

  select ISBN_no "ISBN", item_qty*PRICE "Order Sum"
    from order_books
    where Isbn_no like '%8'
    OR Isbn_no like '0%'
    AND item_qty*PRICE < 100 
    order by ISBN_NO , 2 DESC;

  The result should be:

  ISBN	Order Sum
  0201703092	78
  0471777781	64
  0672325764	49
  0764557599	84
  0764557599	42
  0764579088	140