MySQL Cookbook

17.2 Displaying Query Results as Paragraph Text

17.2.1 Problem

You want to display a query result as free text.

17.2.2 Solution

Display it with no surrounding HTML structure other than paragraph tags.

17.2.3 Discussion

Paragraphs are useful for displaying free text with no particular structure. In this case all you need to do is retrieve the text to be displayed, encode it to convert special characters to the corresponding HTML entities, and wrap each paragraph within <p> and </p> tags. The following examples show how to produce a paragraph for a status display that includes the current date and time, the server version, the client username, and the current database name (if any). These values are available from the following query:

mysql> SELECT NOW( ), VERSION( ), USER( ), DATABASE( );
+---------------------+-----------------+----------------+------------+
| NOW( )               | VERSION( )       | USER( )         | DATABASE( ) |
+---------------------+-----------------+----------------+------------+
| 2002-05-18 11:33:12 | 4.0.2-alpha-log | paul@localhost | cookbook   |
+---------------------+-----------------+----------------+------------+

In Perl, the CGI.pm module provides a p( ) function that adds paragraph tags around the string you pass to it. p( ) does not HTML-encode its argument, so you should take care of that by calling escapeHTML( ):

($now, $version, $user, $db) =
    $dbh->selectrow_array ("SELECT NOW( ), VERSION( ), USER( ), DATABASE( )");
$db = "NONE" unless defined ($db);
$para = <<EOF;
Local time on the MySQL server is $now.
The server version is $version.
The current user is $user.
The current database is $db.
EOF
print p (escapeHTML ($para));

In PHP, you can print the <p> and </p> tags around the encoded paragraph text:

$query = "SELECT NOW( ), VERSION( ), USER( ), DATABASE( )";
$result_id = mysql_query ($query, $conn_id);
if ($result_id)
{
    list ($now, $version, $user, $db) = mysql_fetch_row ($result_id);
    mysql_free_result ($result_id);
    if (!isset ($db))
        $db = "NONE";
    $para = "Local time on the MySQL server is $now."
                . " The server version is $version."
                . " The current user is $user."
                . " The current database is $db.";
    print ("<p>" . htmlspecialchars ($para) . "</p>\n");
}

Or, after fetching the query result, you can print the paragraph by beginning in HTML mode and switching between modes:

<p>
Local time on the MySQL server is
<?php print (htmlspecialchars ($now)); ?>.
The server version is
<?php print (htmlspecialchars ($version)); ?>.
The current user is
<?php print (htmlspecialchars ($user)); ?>.
The current database is
<?php print (htmlspecialchars ($db)); ?>.
</p>

To display a paragraph in Python, do something like this::

cursor = conn.cursor ( )
cursor.execute ("SELECT NOW( ), VERSION( ), USER( ), DATABASE( )")
row = cursor.fetchone ( )
if row is not None:
    if row[3] is None:  # check database name
        row[3] = "NONE"
    para = ("Local time on the MySQL server is %s." +
            " The server version is %s." +
            " The current user is %s." +
            " The current database is %s.") % (row)
    print "<p>" + cgi.escape (para, 1) + "</p>"
cursor.close ( )

In JSP, the display might be produced as follows:

<sql:query var="rs" dataSource="${conn}">
    SELECT NOW( ), VERSION( ), USER( ), DATABASE( )
</sql:query>
<c:set var="row" value="${rs.rowsByIndex[0]}" />
<c:set var="db" value="${row[3]}" />
<c:if test="${empty db}">
    <c:set var="db" value="NONE" />
</c:if>

<p>
Local time on the server is <c:out value="${row[0]}" />.
The server version is <c:out value="${row[1]}" />.
The current user is <c:out value="${row[2]}" />.
The current database is <c:out value="${db}" />.
</p>

The JSP script uses rowsByIndex so that the result set row's columns can be accessed by numeric index.