Employee Cost Centre Details Query

SELECT pcak.segment2 cost_centre,ffvt.DESCRIPTION
FROM pay_cost_allocation_keyflex pcak
,fnd_flex_values ffv
,fnd_flex_values_tl ffvt
WHERE pcak.cost_allocation_keyflex_id =
(SELECT pcaf.cost_allocation_keyflex_id
FROM pay_cost_allocations_f pcaf
WHERE pcaf.assignment_id =
(SELECT paaf.assignment_id
FROM per_all_assignments_f paaf
WHERE paaf.person_id =
(SELECT papf.person_id
FROM per_all_people_f papf
WHERE papf.employee_number = '1001'
AND papf.effective_end_date > SYSDATE)
AND paaf.effective_end_date > SYSDATE)
AND pcaf.effective_end_date > SYSDATE)
AND pcak.end_date_active IS NULL
and ffv.FLEX_VALUE = pcak.segment2
and ffvt.FLEX_VALUE_ID = ffv.FLEX_VALUE_ID