Show NULL value as pivoted column in SQL Server -

i need pivot count of values matches "animal type" in code sample below. unfortunately may missing records in col2 ('a','b'), need count animal type in 'a','b', or null. need pivot null column count value. doing sum across pivoted columns @ end of query, , null values in col2 not match total.

declare @testdata   table   (   col1    varchar(10)                             ,   col2    varchar(10)                             )  insert @testdata    values ('dog','a') insert @testdata    values ('cat','b') insert @testdata    values ('rabbit',null)  select * @testdata  select       pvt.col1         [animal type] ,   pvt.a            [a] ,   pvt.b            [b] ,   total.records    [total count]    (             select                  col1             ,   col2             ,   count(*)     records                @testdata                group                 col1             ,   col2         )    s pivot         (             sum(records)                 col2 in ([a], [b])         )    pvt join    (             select                  col1                 ,   count(*)     records                @testdata             group                 col1         )    total               on  pvt.col1 = total.col1    

modify col2 in subquery isnull function shown below:

select       pvt.col1         [animal type] ,   pvt.a            [a] ,   pvt.b            [b] ,   pvt.[null]       [null] ,   total.records    [total count]    (             select                  col1             ,   isnull(col2,'null') col2             ,   count(*)     records                @testdata                group                 col1             ,   col2         )    s pivot         (             sum(records)                 col2 in ([a], [b], [null])         )    pvt join    (             select                  col1                 ,   count(*)     records                @testdata             group                 col1         )    total               on  pvt.col1 = total.col1