Mysql multiline statement causes syntax error // php, using wordpress to send a raw query string
    $output = $wpdb-&gt;query("
      INSERT INTO wp_priceGrids (gridId) VALUES (NULL); SELECT MAX(gridId) FROM wp_priceGrids;
    ");


Results in:

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 'SELECT MAX(gridId) FROM wp_priceGrids' at line 1]
INSERT INTO wp_priceGrids (gridId) VALUES (NULL); SELECT MAX(gridId) FROM wp_priceGrids;


Tried


Deleting / commenting the 2nd line. Works. A new row is added and
visible as I check through CLI 
Adding backticks (``) around the
field name gridId. Seems not to affect anything, error is the same
Removing the hard return between statements (as you can see above).
No change


Question

Is it a syntax error? I've checked against examples and I think what I have matches their formats

owner@G700:~$ mysql --version
mysql  Ver 14.14 Distrib 5.7.25, for Linux (x86_64) using  EditLine wrapper
owner@G700:~$ php --version
PHP 7.2.15-0ubuntu0.18.04.1 (cli) (built: Feb  8 2019 14:54:22) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
    with Xdebug v2.7.0, Copyright (c) 2002-2019, by Derick Rethans
    with Zend OPcache v7.2.15-0ubuntu0.18.04.1, Copyright (c) 1999-2018, by Zend Technologies
Your multiquery is subject to a race condition. You may not get back the value of the insert you do.

Use insert-id like:

$output = $wpdb-&gt;query("
      INSERT INTO wp_priceGrids (gridId) VALUES (NULL)";
$lastid = $wpdb-&gt;insert_id;


I've also heard the multiquery aspect of the mysql protocol is generally considered a mistake. Recommend avoiding it.