Oracle: Subquery resultset

Oracle: Subquery resultset

I have qry below, is this the right way to do subqry SELECT
App.State_Pstl_Name,
COUNT (DISTINCT App.APLCTN_ID) AS Total_APLCTN
FROM
(
Select
count(distinct b.APLCTN_ID ),
A.Aplctn_Sk,
b.APLCTN_ID,
A.Lctn_Sk,
b.APLCTN_CREATD_DT,
B.Aplctn_Sbmtd_Dt,
c.STATE_PSTL_CD,
c.STATE_PSTL_NAME,
C.Urbn_Rrl_Ind
From MIDAS.Ee_Application_Mmbr_Fact A,
MIDAS.Insrnc_Aplctn_Dmnsn B,
Midas.Lctn_Dmnsn C
Where A.Lctn_Sk In (Select Lctn_Sk From Midas.Lctn_Dmnsn Where
Flag_Actv_Rec = 'Y' )
And A.Aplctn_Sk in ( select Aplctn_Sk from MIDAS.Insrnc_Aplctn_Dmnsn Where
Flag_Actv_Rec = 'Y' )
AND ( b.APLCTN_CREATD_DT >= '01-JUL-13' OR b.APLCTN_CREATD_DT <=
'01-JUL-31' )
GROUP BY A.Aplctn_Sk,
b.APLCTN_ID,
a.LCTN_SK,
b.APLCTN_CREATD_DT,
B.Aplctn_Sbmtd_Dt,
c.STATE_PSTL_CD,
c.STATE_PSTL_NAME,
c.URBN_RRL_IND
) App
GROUP BY
App.STATE_PSTL_NAME
Order By
App.State_Pstl_Name