ERROR (internal_error): Operation on mixed SRID geometries
I got this issue when I tried to optimize a pgsql code with postgis. See the following example that works with if you join it with other sentence: SELECT ST_SetSRID(ST_MakeLine(ST_MakePoint(4.51, 52.2), ST_MakePoint(23.42, 37.58)),4326) But, if you only replace ST_MakePoint by a geom selection you will have an error: SELECT ST_SetSRID(ST_MakeLine( (select point from nodes where name='3'), (select point from nodes where name='20')) ,4326) ERROR: Operation on mixed SRID geometries SQL state: XX000 To solve it just delete ST_SetSRID as follows: SELECT ST_MakeLine( (select point from nodes where name='3'), (select point from nodes where name='20')) Now it works Enjoy it!