SQL Server 2008数据透视表与日期

Question

I have the following dataset:

site    documentation_category  expiry_date
-------------------------------------------
Liverpool   Treatment Bed Inspection    2015-03-07 00:00:00.000
Liverpool   Treatment Bed Inspection    2015-03-04 00:00:00.000
Watford Treatment Bed Inspection    2015-03-04 00:00:00.000
Leeds   Gas Safety Record   2015-02-27 00:00:00.000

And I am trying to create the following pivot table:

site  1  2
----------------------------------
Leeds  NULL  2015-02-27 00:00:00.000
Liverpool  2015-03-07 00:00:00.000  NULL
Watford  2015-03-04 00:00:00.000  NULL

But I get the following:

site  1  2
----------------
Leeds  NULL  NULL
Liverpool  NULL  NULL
Watford  NULL  NULL

When using the following code:

SELECT
[site],
[1],
[2]
FROM
(SELECT
    [site],
    [documentation_category],
    [expiry_date]
FROM
    testing) AS p
PIVOT
(
    MAX([expiry_date])
FOR [documentation_category] IN
    ([1], [2])
) AS pvt;

Thanks in advance.

Answer 1

Without using a dynamic SQL approach I think you have to actually name the column values to pivot on like this:

SELECT
  [site],
  [Treatment Bed Inspection],
  [Gas Safety Record]
FROM
(SELECT
    [site],
    [documentation_category],
    [expiry_date]
FROM
    testing) AS p
PIVOT
(
    MAX([expiry_date])
FOR [documentation_category] IN
    ([Treatment Bed Inspection], [Gas Safety Record])
) AS pvt
ORDER BY [site];

This will produce the following result:

site      Treatment Bed Inspection Gas Safety Record
--------- ------------------------ -----------------------
Leeds     NULL                     2015-02-27 00:00:00.000
Liverpool 2015-03-07 00:00:00.000  NULL
Watford   2015-03-04 00:00:00.000  NULL

(3 row(s) affected)

This could work if you only ever want to pivot on Treatment Bed Inspection and Gas Safety Record but if you expect a lot of different values and want to pivot on all you should build the query dynamically. Search this site for dynamic pivot sql . It's a quite common question and has been answered many times before.