rewrite wpdb help

global $wpdb, $_current_member;

    $paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
    $post_per_page = 2;
    $offset = ($paged - 1)*$post_per_page;

    $activityTable = $wpdb->prefix . 'ams_activity';
    $activityMetaTable = $wpdb->prefix . 'ams_activity_meta';

$activity_calls =
    $wpdb->get_results(
        $wpdb->prepare("
            SELECT SQL_CALC_FOUND_ROWS
                a.*, m.*
            FROM
                $activityTable a
            LEFT OUTER JOIN
                (SELECT activity_id, meta_key, meta_value FROM $activityMetaTable)
            AS
                m
            ON
                a.id = m.activity_id
            WHERE
                a.user_id = %d
            AND
                a.type = %s
            OR
                a.type = %s
            OR
                a.type = %s
            ORDER BY
                time DESC
            LIMIT
                %d, %d"
            , $_current_member->ID
            , 'status_update'
            , 'motivation_update'
            , 'measurement_update'
            , $offset
            , $post_per_page
            ), OBJECT);


    $sql_posts_total = $wpdb->get_var( "SELECT FOUND_ROWS();" );
    $max_num_pages = ceil($sql_posts_total / $post_per_page);


            foreach ($activity_calls as $row) {
    //removed irrelevant loop stuff

            }

// this code adapted from ( http://wp.smashingmagazine.com/2013/09/26/powerful-wordpress-tips-and-tricks/ )
$pagination = array(
    'base'       => str_replace( 99999, '%#%', get_pagenum_link( 99999 ) ),
    'format'     => '?paged=%#%',
    'current'    => max( 1, get_query_var( 'paged' ) ),
    'total'      => $max_num_pages,
    'next_text'  => 'next',
    'prev_text'  => 'previous'
);
echo '<div class="pagination primary-links">' . paginate_links( $pagination ) . '</div>';