Opencart - SQL to Delete customers of a specifi Users Group and move all the customers to the 1st users group

In this example we delete all the customers of the group with ID 3 and move all the other customers to the first group



DELETE FROM oc_customer_activity WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);

DELETE FROM oc_customer_history WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);

DELETE FROM oc_customer_ip WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);

DELETE FROM oc_customer_online WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);

DELETE FROM oc_customer_reward WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);

DELETE FROM oc_customer_transaction WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);


DELETE FROM oc_address WHERE customer_id IN (
 SELECT oc_customer.customer_id  FROM `oc_customer` where customer_group_id != 3
);

DELETE FROM oc_customer WHERE customer_group_id != 3;



/*moving all the users to the 1st customer_group_id 1 */
UPDATE `oc_customer` SET `customer_group_id` = '1'