Question

I have a contacts table:

ID  NAME
--- ----
1   KK
2   JKI
3   HU

And I have a phone table:

ID  ContactID  Phone  Type
--- ---------  -----  --------
1   1          569    Business
2   1          896    Mobile
3   1          258    Fax
4   2          369    Mobile
5   3          124    Fax
6   2          496    Fax

I want to get all contacts with at least one phone number. The phone number to be displayed should be Business, if there are no Busniess Type available, then Mobile, if there are no Mobile type available then Fax else null

Sample Result:

ID  NAME   PHONE
--- ------ ------
1   KK     569   -- Business present
2   JKI    369   -- Business not present but mobile present
3   HU     124   -- only fax present

Answer 1

;WITH [prior](i,t) AS 
(
    SELECT 1, 'Business'
    UNION ALL SELECT 2, 'Mobile'
    UNION ALL SELECT 3, 'Fax'
),
x AS 
(
  SELECT c.ID, c.Name, p.Phone,
    rn = ROW_NUMBER() OVER (PARTITION BY c.ID ORDER BY r.i)
  FROM dbo.Contacts AS c
  LEFT OUTER JOIN dbo.Phone AS p
  ON p.ContactID = c.ID
  LEFT OUTER JOIN [prior] AS r
  ON r.t = p.[Type]
)
SELECT ID, Name, Phone FROM x
WHERE rn = 1;

If you want to eliminate contacts with no phones, just change both instances of LEFT OUTER to INNER.