SQL Server - Include NULL using UNPIVOT

Question

UNPIVOT will not return NULLs, but I need them in a comparison query. I am trying to avoid using ISNULL the following ex

Answer 1

I've found left outer joining the UNPIVOT result to the full list of fields, conveniently pulled from INFORMATION_SCHEMA, to be a practical answer to this problem in some contexts.

-- test data
CREATE TABLE _t1(name varchar(20),object_id varchar(20),principal_id varchar(20),schema_id varchar(20),parent_object_id varchar(20),type varchar(20),type_desc varchar(20),create_date varchar(20),modify_date varchar(20),is_ms_shipped varchar(20),is_published varchar(20),is_schema_published varchar(20))
INSERT INTO _t1 SELECT 'blah1', 3, NULL, 4, 0, 'blah2', 'blah3', '20100402 16:59:23.267', NULL, 1, 0, 0 

-- example
select c.COLUMN_NAME, Value
from INFORMATION_SCHEMA.COLUMNS c
left join (
  select * from _t1
) q1
unpivot (Value for COLUMN_NAME in (name,object_id,principal_id,schema_id,parent_object_id,type,type_desc,create_date,modify_date,is_ms_shipped,is_published,is_schema_published)
) t on t.COLUMN_NAME = c.COLUMN_NAME
where c.TABLE_NAME = '_t1'

output looks like:

+----------------------+-----------------------+
|    COLUMN_NAME       |        Value          |
+----------------------+-----------------------+
| name                 | blah1                 |
| object_id            | 3                     |
| principal_id         | NULL                  | <======
| schema_id            | 4                     |
| parent_object_id     | 0                     |
| type                 | blah2                 |
| type_desc            | blah3                 |
| create_date          | 20100402 16:59:23.26  |
| modify_date          | NULL                  | <======
| is_ms_shipped        | 1                     |
| is_published         | 0                     |
| is_schema_published  | 0                     |
+----------------------+-----------------------+