SQL SELECT Columns From Multiple Tables Without Repeating Data
SELECT Phone.Phone, Email.Email FROM Contacts.Phone, Contacts.Email
WHERE Phone.ContactId = :contactId AND Email.ContactId = :contactId

Row 1: 555-555-5555 - email@email.com
Row 2: 666-666-6666 - email@email.com

Row 1: 555-555-5555 - email@email.com
Row 2: 666-666-6666 - NULL

SELECT 'EMAIL', Email.Email
  FROM Contacts.Email
 WHERE Email.ContactId = :contactId
UNION ALL
SELECT 'PHONE', Phone.Phone
  FROM Contacts.Phone
 WHERE Phone.ContactId = :contactId
 ORDER BY 1 -- put e-mail addresses before phone-numbers
;

SELECT Phone.Phone,
    CASE Email.Email
    WHEN @curEmail THEN NULL
    ELSE @curEmail := Email.Email END AS Email
FROM Contacts.Phone, Contacts.Email, (SELECT @curEmail := '') AS r
WHERE Phone.ContactId = :contactId AND Email.ContactId = :contactId

Row 1: 555-555-5555 - email@email.com
Row 2: 666-666-6666 - NULL

SELECT
    Phone.Phone,
    Email.Email
FROM
    Contacts.Phone

Left Outer Join Contacts.Email ON Phone.ContactId = Email.ContactId

Row 1: 555-555-5555 - email@email.com
Row 2: 666-666-6666 - NULL