Copy districts from one db to another with differing province id's.

README.md

Local districts table:

`id`, `name`, `province_id`

Local provinces table:

`id`, `name`

Task: copy districts over from another DB with a different provinces table and different province id's.

1. Add a temporary city_name to your local districts table.

2. Run Copy_districts.sql.

3. Review non-matching districts:

    SELECT * FROM districts
    LEFT JOIN provinces ON provinces.name LIKE districts.city_name;
   

4. Remove the temporary city_name from districts.

Copy_districts.sql

INSERT districts
    SELECT
        NULL
        , district_other.name
        , district_other.province_other_id
        , IFNULL(province_other.name, '')
    FROM other_db.district_other
        LEFT JOIN other_db.province_other ON province_other.id = district_other.province_other_id
;

UPDATE districts
    LEFT JOIN province ON province.name LIKE districts.province_name
SET province_id = province.id
;