International PHP Conference 2015

MySQL extension overview example

This simple example shows how to connect, execute a query, print resulting rows and disconnect from a MySQL database.

Example #1 MySQL extension overview example

<?php
// Connecting, selecting database
$link mysql_connect('mysql_host''mysql_user''mysql_password')
    or die(
'Could not connect: ' mysql_error());
echo 
'Connected successfully';
mysql_select_db('my_database') or die('Could not select database');

// Performing SQL query
$query 'SELECT * FROM my_table';
$result mysql_query($query) or die('Query failed: ' mysql_error());

// Printing results in HTML
echo "<table>\n";
while (
$line mysql_fetch_array($resultMYSQL_ASSOC)) {
    echo 
"\t<tr>\n";
    foreach (
$line as $col_value) {
        echo 
"\t\t<td>$col_value</td>\n";
    }
    echo 
"\t</tr>\n";
}
echo 
"</table>\n";

// Free resultset
mysql_free_result($result);

// Closing connection
mysql_close($link);
?>

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User Contributed Notes 1 note

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zjrwjzzz at 163 dot com
6 months ago
Be aware that if you are trying to foreach the associative array returned by mysql_fetch_array() with MYSQL_ASSOC or mysql_fetch_assoc(), you have to ensure the return value that is used in foreach structure is exactly a array rather than a FALSE value.

Or you might encounter the warning below:
    Warning: Invalid argument supplied for foreach()

Here is an example (assume that $result have already stored the return value from mysql_query()):

If you have some block of code like:

<?php

// Printing results in HTML
echo "<table>\n";
while (
$line = mysql_fetch_array($result, MYSQL_ASSOC)) {
    echo
"\t<tr>\n";
    foreach (
$line as $col_value) {
        echo
"\t\t<td>$col_value</td>\n";
    }
    echo
"\t</tr>\n";
}
echo
"</table>\n";

?>

If this is the case, you should use the code below instead:

<?php

// Check ahead, before using it
if (mysql_num_rows($result) > 0) {
   
// Printing results in HTML
   
echo "<table>\n";
    while (
$line = mysql_fetch_array($result, MYSQL_ASSOC)) {
        echo
"\t<tr>\n";
        foreach (
$line as $col_value) {
            echo
"\t\t<td>$col_value</td>\n";
        }
        echo
"\t</tr>\n";
    }
    echo
"</table>\n";
}

?>
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