只获得今天的帖子?

i need to have a function that will echo the post that has been posted today.

from 00.00 to 23.59 . ihave created a function but it is not giving the result i need here is my function:

function todayNews() {
    $id = mysql_real_escape_string ($id);
    $sql = 'SELECT * FROM wp_posts WHERE  post_status = "publish" AND post_date = CURRENT_DATE  ORDER BY post_date DESC LIMIT 15';
    $res = mysql_query($sql) or die (mysql_error());

if (mysql_num_rows($res) !=0):
    while ($row = mysql_fetch_assoc($res)) {

    $title = ($row['post_title']);

    $old_date = $row['post_date'];             // returns Saturday, January 30 10 02:06:34
    $old_date_timestamp = strtotime($old_date);
    $new_date = date('H:i', $old_date_timestamp);

    $mycontent = ($row['post_content']);
    $mycontent = strip_tags($mycontent);
    $mycontent = substr($mycontent,0,350);
    $mycontent = preg_replace("/\[caption.*\[\/caption\]/", '', $mycontent); 

    $first_img = '';
    $my1content = $row['post_content'];
    $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $my1content, $matches); 
    $first_img = $matches [1] [0];
    if(empty($first_img)){ //Defines a default image
    $first_img = "/img/default.png";
    }

    echo '


    <ul class="li-sub">
                <li>
'.$title.'
</li>

        </ul>

    ';  
}
    else:
        echo 'There are no posts for today !';
    endif;

} // end  

Thank you !

EDIT: Post_date have this format : Y-m-d H:i

You are comparing POST_DATE which is a datetime with CURRENT_DATE which is a Date , it won't give any result.

you can try the following SQL

$sql = 'SELECT * FROM wp_posts WHERE  post_status = "publish" AND DATE(post_date) = CURRENT_DATE  ORDER BY post_date DESC LIMIT 15';

This will convert the post_date to only date before comparing with current date.