select di.seq, di.node , di.edge , di.cost, a.geom
from pgr_dijkstra(
'select id, target, source, sum(cost) from pedroad',
array(select get_source2('location1'))
,array(select get_target2('test4'))
,false) as di,
pedroad a
where di.node = a.source;
error: column "pedroad.id" must appear in the GROUP BY clause or be used in an aggregate function
我应该如何使用group by
?