Please help with the below SQL to get the counts: as counts in groups of 4. It is giving error of "expression containing an aggregate or a subquery". How can I get the counts?

SELECT

CASE WHEN c. PRTNR_TYPE_CD is NULL THEN

( Case when c. par_ou_id is not null then 'SUBSIDIARY' ELSE

Case when C. row_id in (

select distinct par_ou_id

from

COMMON. dbo. W_SBL_S_ORG_EXT

where

par_ou_id is not null

)

then 'PARENT' ELSE

'SELF-PARENTED' END END )

ELSE NULL

END , COUNT ( 1)