Oracle Cloud ERP – Buyer Query

SELECT pu.username
from per_user_roles pur,
	per_users pu,
	per_roles_dn_tl prdt,
	per_roles_dn prd,
	per_user_roles pur1,
	per_users pu1,
	per_roles_dn_tl prdt1,
	per_roles_dn prd1

WHERE pu.user_id = pur.user_id
AND prdt.role_id = pur.role_id
AND prdt.role_id = prd.role_id
AND prdt.language = USERENV ('lang')
AND pu.active_flag = 'Y'
and prdt.role_name in ('Buyer')
and pu1.user_id = pur1.user_id
AND prdt1.role_id = pur1.role_id
AND prdt1.role_id = prd1.role_id
AND prdt1.language = USERENV ('lang')
AND pu1.active_flag = 'Y'
and prdt1.role_name in ('Procurement Manager')
and pu1.user_guid = FND_GLOBAL.USER_GUID

UNION 
 
select distinct pu.username
		from per_user_roles pur,
		per_users pu,
		per_roles_dn_tl prdt,
		per_roles_dn prd
		where pu.user_id = pur.user_id
		AND prdt.role_id = pur.role_id
		AND prdt.role_id = prd.role_id
		AND prdt.language = USERENV ('lang')
		AND pu.active_flag = 'Y'
		and prdt.role_name not in ('Procurement Manager')
		and prdt.role_name in ('Buyer')
		and pu.user_guid = FND_GLOBAL.USER_GUID