sql 多行合并为一行

我想要将多行合并一行
select a.outpatient_code, b.value from PT_OUTPATIENT_CURE a,RCD_out_RECORD_ITEM b
where a.id=b.outpatient_id
and a.outpatient_code='685593'
and b.element_id='204032'

有办法吗

select a.outpatient_code, listagg(b.value) within group (order by b.value) 
from PT_OUTPATIENT_CURE a,RCD_out_RECORD_ITEM b
where a.id=b.outpatient_id
and a.outpatient_code='685593'
and b.element_id='204032'
group by a.outpatient_code