Update MySQL table based on results for joining to tables - mysql

Question

I have three tables, emails, person_details and data_providers. Basically all of my users id, email, and current assigned data_providers_id are stored in the emails table.
The second table, person_details contains demographic information collected by multiple data providers, each row identified by an emails_id that is relational to the emails.id data_providers_id that is relational to the third table data_providers.id
The third table, data_providers contains each of my data providers id, name, and precedence.
Basically, a users information could be collected from multiple sources, and I need to UPDATE emails set data_providers_id = based on a select that would JOIN the person_details table and the data_providers table sorting by data_providers.precedence DESC then person_details.import_date ASC and use the first value (highest precedence, then oldest import_date).
I was trying to build the query, but my subquery is returning more than one row. This query is a little over my head, hoping someone more experienced with complex queries might be able to point me in the right direction.
UPDATE emails
SET emails.data_providers_id =
SELECT person_details.data_providers_id
FROM person_details
LEFT JOIN data_providers ON person_details.data_providers_id = data_providers.id
ORDER BY data_providers.percent_payout ASC, person_details.import_date ASC ;
Here are some details about the three tables if this helps. Any guidance would be MUCH appreciated. Thanks in advance :)
emails table:
+-------------------+---------------------+------+-----+---------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------------------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| data_providers_id | tinyint(3) unsigned | NO | MUL | NULL | |
| email | varchar(255) | NO | UNI | NULL | |
+-------------------+---------------------+------+-----+---------------------+----------------+
person_details:
+-------------------+---------------------+------+-----+---------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| emails_id | int(11) unsigned | NO | PRI | NULL | |
| data_providers_id | tinyint(3) unsigned | NO | PRI | NULL | |
| fname | varchar(255) | YES | | NULL | |
| lname | varchar(255) | YES | | NULL | |
| address_line1 | text | YES | | NULL | |
| address_line2 | text | YES | | NULL | |
| city | varchar(255) | YES | | NULL | |
| state | varchar(2) | YES | | NULL | |
| zip5 | varchar(5) | YES | | NULL | |
| zip4 | varchar(4) | YES | | NULL | |
| home_phone | varchar(10) | YES | | NULL | |
| mobile_phone | varchar(10) | YES | | NULL | |
| work_phone | varchar(10) | YES | | NULL | |
| dob | date | YES | | NULL | |
| gender | varchar(1) | YES | | NULL | |
| ip_address | varchar(15) | NO | | NULL | |
| source | varchar(255) | NO | | NULL | |
| optin_datetime | datetime | NO | MUL | NULL | |
| import_date | timestamp | NO | | 0000-00-00 00:00:00 | |
+-------------------+---------------------+------+-----+---------------------+-------+
data_providers table:
+-----------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+---------------------+------+-----+---------+----------------+
| id | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(255) | NO | | NULL | |
| precedence | int(2) | YES | | 0 | |
+-----------------+---------------------+------+-----+---------+----------------+

Answer 1

To use a SELECT as an expression you have to put it in parentheses. And to get the first value, use LIMIT 1:
UPDATE emails
SET emails.data_providers_id = (
SELECT person_details.data_providers_id
FROM person_details
LEFT JOIN data_providers ON person_details.data_providers_id = data_providers.id
WHERE person_details.emails_id = emails.id
ORDER BY data_providers.percent_payout ASC, person_details.import_date ASC
LIMIT 1) ;