<?php
mysql_connect("localhost", "sql kullanici adi", "sql sifre");
mysql_select_db("db adi");

$q = mysql_query("select id,post_content from wp_posts where post_content like '%more%'");
while($s = mysql_fetch_assoc($q)) {
    $pid = $s["id"];
    $content= $s["post_content"];
    $exp = explode('<!--more-->',$content);
        if($exp[0]!=''){
            $w = $exp[0].' <!--more-->';
            mysql_query("update wp_posts set post_content='".mysql_real_escape_string($w)."' where post_id='$pid'");
        }
}

?>