declare @xml xml = '<orga_label>ORG1</orga_label><orga_label>ORG2</orga_label><orga_label>ORG3</orga_label>';
select stuff((select
',' + s from (
select
a.b.value('(.)[1]', 'varchar(50)') s
from @xml.nodes('/orga_label') a(b)
) t
for xml path('')
),1,1,'');