如何查询具有相同字段的两个表，仅当字段值相同时才返回 id

Question

I have two tables (email and phone) that indicate if a message was opened (read/listened). I need to find the id's of the member's who have not opened the message (they could have been sent an email and called). So the only case in which they did not receive the message is if they did not open the email or answer the phone.

I have a query that looks like this to know if they opened it:

SELECT person_id, last_name, first_name
      FROM person 
     WHERE person_id IN (
          SELECT DISTINCT person_id 
          FROM (
            SELECT person_id
              FROM msg_email WHERE message_id = ? AND opened = 'Y'
            UNION ALL
            SELECT person_id
              FROM msg_voice WHERE message_id = ? AND opened = 'Y') tt
         )
 ORDER BY last_name ASC, first_name ASC"

However, this only works for knowing if it was opened via either of the delivery methods.

How would I fashion a query to find the person ids of those that received the message (exists is one of the two tables), but the opened value is 'N' exclusively in both tables?

Sample Data person table

person_id  firstname lastname
    1         Joe       Smith
    2         Tom       Jones

msg_email table

message_id  person_id  opened
    1            1       N
    1            2       Y

msg_phone table

message_id  person_id  opened
    1            1        N
    1            2        N

So I need a query that will only return Joe Smith

Answer 1

Hmmm, one method is a series of EXISTS / IN conditions:

SELECT p.person_id, p.last_name, p.first_name
FROM person p
WHERE EXISTS (SELECT 1
              FROM msg_email e
              WHERE e.person_id = p.person_id AND e.opened = 'N'
             ) AND
      NOT EXISTS (SELECT 1
                  FROM msg_email e
                  WHERE e.person_id = p.person_id AND e.opened = 'Y'
                 ) AND
      EXISTS (SELECT 1
              FROM msg_voice v
              WHERE v.person_id = p.person_id AND v.opened = 'N'
             ) AND
      NOT EXISTS (SELECT 1
                  FROM msg_voice v
                  WHERE v.person_id = p.person_id AND v.opened = 'Y'
                 )
ORDER BY last_name ASC, first_name ASC;

I recommend EXISTS over IN because it usually has better performance. That will be true if you have indexes on msg_email(person_id, opened) and msg_voice(person_id, opened) .

EDIT:

It occurs to me that you want 'N' in either table along with no 'Y' in both tables. The logic is similar but:

SELECT p.person_id, p.last_name, p.first_name
FROM person p
WHERE (EXISTS (SELECT 1
               FROM msg_email e
               WHERE e.person_id = p.person_id AND e.opened = 'N'
              ) OR
       EXISTS (SELECT 1
               FROM msg_voice v
               WHERE v.person_id = p.person_id AND v.opened = 'N'
              )
      ) AND
      NOT EXISTS (SELECT 1
                  FROM msg_email e
                  WHERE e.person_id = p.person_id AND e.opened = 'Y'
                 ) AND
      NOT EXISTS (SELECT 1
                  FROM msg_voice v
                  WHERE v.person_id = p.person_id AND v.opened = 'Y'
                 )
ORDER BY last_name ASC, first_name ASC;