[postgis-users] ERROR Update query with ST_Line_Locate_Point

Chris Kelley iamchriskelley at gmail.com
Sat Apr 7 18:55:56 PDT 2012

PLEASE DISREGARD -- The answer is obvious and unrelated to postgis (SQL
noob error).

On Sat, Apr 7, 2012 at 7:41 PM, Chris Kelley <iamchriskelley at gmail.com>wrote:

> Hi,
> Using postgis 1.5 to update a table of points along a line with their
> fractional position along that line. I have confirmed that a select query
> returns good results:
> select st_line_locate_point(a.the_geom, b.the_geom) as line_frac from
> road_table a, points_table b;
> This does not work properly however if I use an update query:
> update points_table set line_frac = st_line_locate_point(a.the_geom,
> b.the_geom) from road_table a, points_table b;
> In that case, the query still processes but all line_frac entries in
> points_table have what is the highest value in the select query; i.e. the
> value that should only belong to the point furthest down the road.
> Does anyone know what's going on here and how to fix it? Didn't find
> anything on this online.
> Thanks,
> Chris
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