SQL对表中的每一列在结果中返回1行

Question

Admittedly I'm not good with pivot/unpivot, but it seems like that relates to a more direct "transpose" than what I'm looking for. What I need to do is create a results set with 1 row for each of a set of columns in a table.

Quarters Table:

USER    Q1  Q2  Q3  Q4
-----------------------
USER1   1   5   3   3
USER2   2   1   1   8

Desired Results:

USER    Q   V
--------------
USER1   Q1  1
USER1   Q2  5
USER1   Q3  3
USER2   Q4  3
USER2   Q1  2
USER2   Q2  1
USER2   Q3  1
USER2   Q4  1

Answer 1

A "funny" way of do it would be using CROSS APPLY :

SELECT  Q.[USER],
        X.Q,
        X.V
FROM dbo.Quarters Q
CROSS APPLY 
(
    VALUES
        ('Q1', t.Q1),
        ('Q2', t.Q2),
        ('Q3', t.Q3),
        ('Q4', t.Q4)
) X (Q, V);

Answer 2

Using UNPIVOT the query becomes even simpler. with UNPIVOT the query would look something like....

Select Users 
     , Q 
     , V
FROM TableName
  UNPIVOT (
            V FOR Q IN (Q1,Q2,Q3,Q4)
           )up

Answer 3

make sure the value used to eliminate null is not represented in your dataset!

SELECT
    [user]
    ,V = IIF(V = -99999,NULL,V)
    ,Q
FROM
    (
    SELECT
       [user]
       ,Q1 = ISNULL(t.Q1,-99999)
       ,Q2 = ISNULL(t.Q2,-99999)
       ,Q3 = ISNULL(t.Q3,-99999)
       ,Q4 = ISNULL(t.Q4,-99999)
    FROM
       @Table t) p

    UNPIVOT
       (V FOR Q IN (Q1,Q2,Q3,Q4)
       ) as unpvt

To allow for null's per your comment, have to use a hack to set a null value as something else and put it back to null. ( SQL Server - Include NULL using UNPIVOT ) When wanting to include the cross apply method becomes a little more attractive to me.

Seems to me UNPIVOT would work great for you seeing you have a known number of quarters.

And for reference here is the link to Mirosoft's site on PIVOT and UNPIVOT. https://technet.microsoft.com/en-us/library/ms177410(v=sql.105).aspx