我有一个查询（实际上是多个查询）可以在phpmyadmin中完美运行，（我也尝试过get_var 代替get_results, 但我想我可能需要一个替代品$wpdb->prepare. 我怎样才能一次完成这一切？

function myfunction( $campaign_id = 0 ) {
    global $wpdb;
    $coupon_code = $wpdb->get_results(  $wpdb->prepare( "SET @update_code := 0;
                UPDATE " . $wpdb->prefix . "my_table SET status = 1, code = (SELECT @update_code := code)
                WHERE campaign_id = %d AND status IS NULL LIMIT 1;
                SELECT @update_code as code;
                ",$campaign_id ) );
return $coupon_code->code;
}

WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near
\'UPDATE wp_my_table SET status = 1, code = (SELECT @update_code := code)\' at line 2
for query: (runs perfectly in phpmyadmin)
SET @update_code := 0;
UPDATE wp_my_table SET status = 1, code = (SELECT @update_code := code)
WHERE campaign_id = 0 AND status IS NULL LIMIT 1;
SELECT @update_code as code;