How to use pgr_dijkstra many-to-many

Question

I am using pgr_dijkstra(or pgr_dijkstraCost) to find the shortest path and/or cost for drawing isochrone map. Since I need to calculate the shortest path from each of over 100,000 nodes to multiple destinations, I am planning to use pgr_dijkstraCost many-to-many function ↓

http://docs.pgrouting.org/2.2/en/src/dijkstra/doc/pgr_dijkstraCost.html

And, as shown in the example below, I have no problems when I input start_vids and end_vids as a form like ARRAY[2, 7] or ARRAY[3, 11].

SELECT * FROM pgr_dijkstraCost(
    'select id, source, target, cost, reverse_cost from edge_table',
    ARRAY[2, 7],
    ARRAY[3, 11]);

However, what I really want to do is to input arrays by selecting a column from a table. In other words, I want to calculate the shortest path from every single node in my table. For example, I've tried that

SELECT * FROM pgr_dijkstraCost(
    'select id, source, target, cost, reverse_cost from edge_table',
    select array(select source from edge_table),
    ARRAY[3, 11]);

But this returns an error: "ERROR: syntax error at or near "select" / SQL state: 42601 / Character: 171." What's wrong with my code? And, please tell me how to deal with the query result as an input parameter.

Answer 1

You don't need the SELECT of the array, just return the array of the SELECT (in other words, remove the "select"):

SELECT * FROM pgr_dijkstraCost(
    'select id, source, target, cost, reverse_cost from edge_table',
    array(select source from edge_table),
    ARRAY[3, 11]);