Unable to INSERT between tables using ST_GeomFromText - postgresql

Question

I'm trying to insert point geometry values and other data from one table to another table.
-- create tables
create table bh_tmp (bh_id integer, bh_name varchar
, easting decimal, northing decimal, ground_mod decimal);
create table bh (name varchar);
SELECT AddGeometryColumn('bh', 'bh_geom', 27700, 'POINT',3);
-- popualte bh_tmp
insert into bh_tmp values
(1,'C5',542945.0,180846.0,3.947),
(3,'B24',542850.0,180850.0,4.020),
(4,'B26',543020.0,180850.0,4.020);
-- populate bh from bh_tmp
insert into bh(name, bh_geom) SELECT
bh_name,
CONCAT($$ST_GeomFromText('POINT($$, Easting, ' ', Northing, ' '
, Ground_mOD, $$)', 27700)$$);
FROM bh_tmp;
Gives this error:
ERROR: parse error - invalid geometry
SQL state: XX000
Hint: "ST" <-- parse error at position 2 within geometry
I can't see anything wrong with the ST_GeomFromText string that I've specified. But I can populate table bh if I insert rows 'manually', e.g.:
INSERT INTO bh (name, bh_geom)
VALUES ('C5' ST_GeomFromText('POINT(542945.0 180846.0 3.947)', 27700));
What am I doing wrong?

Answer 1

First of all, there is a misplaced semicolon after CONCAT(...);
And you can't concatenate the function name itself into the string:
INSERT INTO bh(name, bh_geom)
SELECT bh_name
, ST_GeomFromText('POINT(' || concat_ws(' ', easting, northing, ground_mod) || ')'
, 27700)
FROM bh_tmp;
Or, since you have values already (not text), you could use ST_MakePoint() and ST_SetSRID():
ST_SetSRID(ST_MakePoint(easting, northing, ground_mod), 27700)
Should be faster.
Npgsql parameterized query output incompatible with PostGIS

Answer 2

You're getting that error because the output of the CONCAT function is text, and your bh_geom column is geometry, so you're trying to insert text into geometry. This will work:
INSERT INTO bh(name, bh_geom) SELECT
bh_name,
ST_GeomFromText('POINT('
|| easting|| ' '
|| Northing
|| ' '
|| Ground_mOD
|| ')', 27700)
FROM bh_tmp;