How to add a new field with a condition on the old one using SQL?

Question

SQL

Hello!
Again there is a task on SQL.
There is a huge DB on clients in Access (more than 5 million records).
Each client has a city.
I have another table in which each city has a region in the adjacent right field.
I would like to add a region to the first table depending on the city (according to the second table)
Can you please tell me how this can be implemented?
Thank you!

Answer 1

1. Modify the table by adding a new city column, which will contain the city.
alter table %clients_table% add region %field type%
2. Using an update-request, set the value of the region name from the region-to-city correspondence table for each record.
update %clients_table% set region = (select region_name from regions_cities where city = %clients_table%.city)

Answer 2

Didn't see access, but maybe left join will help you?