SQL to snap points to the closest line within a predefined radius

snap_points_to_lines.sql

-- Snap the points to their closest lines, found in the subquery below
SELECT
  point_id,
  line_id,
  ST_LINE_INTERPOLATE_POINT(line_geom,
  ST_Line_Locate_Point(line_geom, point_geom)) AS snapped_points --Create the snapped points
FROM 

--Subquery to find the closest line to each point (within a pre-defined raidus)
(
  SELECT DISTINCT ON
    (pt.id) ln.geom AS line_geom,
    pt.geom AS point_geom,
    ln.id AS line_id,
    pt.id AS point_id
  FROM
    point_table AS pt
  INNER JOIN
    line_table AS ln
  ON
    ST_DWithin(pt.geom,
      ln.geom,
      10) -- Snap points to lines within a 10m radius
  ORDER BY
    pt.id,
    ST_Distance(ln.geom,
      pt.geom)) AS closest_pnt; -- Here we order the result set by distance to find the closest line to each point, but as we have used SELECT DISTINCT, we only take the closest point.

Well explained...thanks alot.