php find more similar description from my database not eact match

php find more similar description from my database not eact match

i have mysql classified database
i need to find more similar like more than 60% similar classified ads from
mysql database.
not exact match.
while( $type = mysql_fetch_assoc($result) ){
$node = new sqlNode();
$node->table = "tt_".$type['ID'];
$node->select = "ID, Title, Description, MemberID, PostDate ";
$node->where = " where online = '1'";
if(($categoryR = $mysql->select($node)) === false )
die($mysql->debugPrint());
// this part need to find more similar function
}
please help me