如何在sql查询中检查数组

所以我需要在查询中检查一个数组：

$query = "SELECT * FROM post WHERE ".$select." LIKE '%".$search."%'  AND  ID NOT IN '" .$Lastvar."'";

$Lastvar是我的数组。我不知道从这里到哪里去，如果有任何帮助都将不胜感激。

编辑：这是我的完整查询：

$Lastvar = array();
mysql_select_db('submisions', $dbconn);
$query = "SELECT * FROM post WHERE ".$select." LIKE '%".$search."%' AND ID NOT IN (" . join(", ", $Lastvar) . ")";
$result = mysql_query($query);
$num_rows = mysql_num_rows($result);
if ($num_rows == 0) {
    echo 'No results were found';
    exit;
}