How to resolve pgrouting dijkstra_sp() function error?

Question

insert into dijsktra_results(geom) select ST_UNION(the_geom) from dijkstra_sp('roads_layer',
            (select source_id from roads_layer where gid=9975)::integer,
            (select target_id from roads_layer where gid=2967)::integer);

This query to perform the routing operations. "dijsktra_results" is a newely created table for routing operations with gid and geom columns of 2D(MultiLineString). This is the error I am getting

ERROR:  column "the_geom" does not exist
LINE 1: SELECT gid,the_geom FROM shortest_path('SELECT gid as id, so...
                   ^
QUERY:  SELECT gid,the_geom FROM shortest_path('SELECT gid as id, source::integer, target::integer, length::double precision as cost FROM roads_layer', '1' , '20142' , false, false), roads_layer where edge_id = gid 
CONTEXT:  PL/pgSQL function "dijkstra_sp" line 13 at FOR over EXECUTE statement

********** Error **********

ERROR: column "the_geom" does not exist
SQL state: 42703
Context: PL/pgSQL function "dijkstra_sp" line 13 at FOR over EXECUTE statement

Can anyone resolve this problem or guide for an extent am I gone wrong anywhere.Till now everything worked fine.I calculated vertex_id,edge_id,length.... And how this, dijkstra_sp() function works and calculates the shortest path.

Answer 1

I added table alias sp and r

SELECT r.gid, r.the_geom FROM shortest_path('SELECT gid as id, source::integer, target::integer, length::double precision as cost FROM roads_layer', '1' , '20142' , false, false) as sp , roads_layer as r WHERE sp.edge_id = r.gid

so r.the_geom dosent exists, is it possible that your geometry colum name is geog/geom and not the_geom ?