Copy data into table / multidimensional array

Hello again,

Scenery: I want to copy data from “wp_users” to another table “user”.
SQL
INSERT INTO user(wpUserId, email) SELECT ID, user_email FROM {$wpdb->users} GROUP BY ID;
woulde be sooo easy. So it’s software development and it’s never “easy” and wpdb has query and insert.

query combined with prepare reports an error, it’s about quoting.

$results = $wpdb->get_results(
			$wpdb->prepare(
			"
			INSERT INTO %s ( 'wpUserId', 'email' )
			SELECT ID, user_email FROM {$wpdb->users} GROUP BY ID;
			", $tabname
			)
	);

For the insert I have to split the sql up. So started to get the info

$results = $wpdb->get_results(
			"
			SELECT ID as wpUserId, user_email as email FROM {$wpdb->users} GROUP BY ID;
			", ARRAY_A
);

which results in

Array
	(
	    [0] => Array
	        (
	            [wpUserId] => 1
	            [email] => test@mail.com
	        )

	    [1] => Array
	        (
	            [wpUserId] => 2
	            [email] => anothertest@mail.com
	        )
	)

How to transform that in a key => value array for the insert?
Or is there an easier way which I overlooked?