Creating point at defined distance along line in PostGIS?

Thanks for the help! I've worked out a solution, so I post it here in case someone needs it. This clips 2 meter from the start and the end of each line.

select
        x.name, 
        ST_MakeLine(
                ST_Line_Interpolate_Point(x.myline,  1 - 2/st_length(st_transform(x.myline, 27700))),
                ST_Line_Interpolate_Point(x.myline, 2/st_length(st_transform(x.myline, 27700)))
                )

If I understand you correctly, my suggestion is as follows: run the script

create table your_new_tbl_name as
select ST_EndPoint(ST_Intersection(geom,
ST_Buffer((St_StartPoint(geom)),0.001))) as geom
from your_source_tbl_name

1. Please note that 0,001 = 111,12 m;
2. In this construction, I use a buffer that is built from the first point, with the specified distance, then define a common cut line and select the end point...
3. You can do the same on the endpoint using ST_EndPoint...

Note: the line should not be curve...

if you want to set the required distance in meters, run this query, for example, with a distance of 50 m:

create table your_new_tbl_name as
select ST_EndPoint((ST_Intersection((geom)::geography,
(ST_Buffer((St_StartPoint(geom)::geography),50))))::geometry) as geom
from your_source_tbl_name

This method is called a compass-meter.

my source data is in the geographic coordinate system, with respect... (:-)