postgis - ST_DWithin query throwing 42601 error?

I am trying to get from a particular point more informations about the surroundings (which are also points). So I wrote this:

SELECT *
   FROM osm_point
   WHERE ST_DWithin(way,(ST_SetSRID(ST_MakePoint(12.2385578688105, 51.8435615931295), 4326, 1000);

But there is an error

ERROR: FEHLER: LINE 3: ...T_MakePoint(12.2385578688105, 51.8435615931295), 4326, 1000) ^ SQL state: 42601 Character: 133

What is wrong?

Answer

The SQL error 42601 is a syntax error (see here). Basically, you had an extra opening parenthesis before ST_SetSRID and also a closing missing parenthesis for the same function.

If data type of osm_point.way column is geometry, one needs to cast it to geography in order to ST_DWithin evaluate to geodetic distances (instead of planar distances) and in meters (if units of spatial reference aren't already in meters). The same cast to geography is valid for ST_MakePoint which output is of type geometry and the units of applied CRS 4326 is degrees, but you want meters.

So, use the following query:

SELECT *
FROM osm_point
WHERE ST_DWithin(way::geography, ST_SetSRID(ST_MakePoint(12.2385578688105, 51.8435615931295), 4326)::geography, 1000);

Update: when using ST_DWithin one needs to compare data which have the same SRID. So, if column osm_point.way has a different SRID (you said EPSG:3857) from EPSG:4326 (the SRID you used to define the coordinates with ST_MakePoint), one needs to transform coordinates first. For that use ST_Transform. See:

SELECT * 
FROM osm_point 
WHERE ST_DWithin(ST_Transform(way, 4326)::geography, ST_SetSRID(ST_MakePoint(12.2385578688105, 51.8435615931295), 4326)::geography, 1000);

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About using indexes to speed up your queries, as suggested by Vince, take a look in:

How to properly set up indexes for PostGIS distance queries?.