WordPress: Access Database From Widget Code

If you want to retrieve some information from the database, you can use one of four helper functions to query the database and retrieve the data.

get_results():

This is the function that we looked at earlier. It is best for when you need two-dimensional data (multiple rows and columns). It converts the data into an array that contains separate objects for each row.

get_row():

When you need to find only one particular row in the database (for example, the post with the most comments), you can use get_row(). It pulls the data into a one-dimensional object.

get_col():

This method is much the same as get_row(), but instead of grabbing a single row of results, it gets a single column. This is helpful if you would like to retrieve the IDs of only the top 10 most commented posts. Like get_row(), it stores your results in a one-dimensional object.

get_var():

In many cases, you will need only one value from the database; for example, the email address of one of your users. In this case, you can use get_var to retrieve it as a simple value. The value’s data type will be the same as its type in the database

An example:

<?php
$drafts = $wpdb->get_results("SELECT ID, post_title FROM wp_posts WHERE post_status = 'draft' AND post_author = 5");
foreach ( $drafts as $draft ){
    echo $draft->post_title;
}
?>

Documentation: http://codex.wordpress.org/Class_Reference/wpdb

Source: http://wp.smashingmagazine.com/?p=98071

Hope this helps.

just include wp-blog-header.php in the file

require('yourpath/wp-blog-header.php');

global $wpdb;

$result=$wpdb->get_results("SELECT * FROM table");

var_dump($result);