Error column reference is ambiguous - sql

Question

I have a function which:
compare two columns from different tables
make the insert
How can I get some improvement on this code because I get this error:
ERROR: column reference "fld_id" is ambiguous
SQL state: 42702
line 17 at PERFORM
CREATE OR REPLACE FUNCTION "SA_PRJ".usp_add_timesheet_test(p_uid integer, p_project_id integer, p_allocated_time numeric, p_achieved_time numeric, p_task_desc character varying, p_obs character varying, p_date timestamp without time zone)
RETURNS void AS
$BODY$
BEGIN
DECLARE sum_alloc_time numeric;
DECLARE alloc_hours integer;
DECLARE fld_id integer;
SELECT #sum_alloc_time = SUM(fld_allocated_time)
from "SD_PRJ".tbl_project_timesheet
where fld_project_id = p_project_id;
SELECT #alloc_hours = p.fld_allocated_days, #fld_id = p.fld_id
FROM "SD_PRJ".tbl_project p
INNER JOIN "SD_PRJ".tbl_project_timesheet t
ON p.fld_id=t.fld_id
where t.fld_project_id = p_project_id;
IF #sum_alloc_time <= #alloc_hours THEN
INSERT INTO "SD_PRJ".tbl_project_timesheet(fld_emp_id, fld_project_id, fld_is_allocated,fld_allocated_time, fld_achieved_time, fld_task_desc, fld_obs, fld_date)
VALUES (p_uid,p_project_id,coalesce(alloc_id,0), p_allocated_time, p_achieved_time,p_task_desc, p_obs, p_date);
RAISE NOTICE 'INSERT OK!';
ELSE
RAISE NOTICE 'NOT OK';
END IF;
END;
$BODY$ LANGUAGE plpgsql;
There are two tables:
"SD_PRJ".tbl_project (
fld_id
,fld_allocated_days)
"SD_PRJ".tbl_project_timesheet (
fld_id
, fld_project_id
,fld_allocated_time)

Answer 1

Working version:
CREATE OR REPLACE FUNCTION "SA_PRJ".usp_add_timesheet_test(
p_uid integer, p_project_id integer, p_allocated_time numeric
, p_achieved_time numeric, p_task_desc varchar, p_obs varchar, p_date timestamp)
RETURNS void AS
$func$
DECLARE
_sum_alloc_time numeric;
_alloc_hours integer;
_fld_id integer;
BEGIN
SELECT SUM(fld_allocated_time)
INTO _sum_alloc_time
FROM "SD_PRJ".tbl_project_timesheet
WHERE fld_project_id = p_project_id;
SELECT p.fld_allocated_days, p.fld_id
INTO _alloc_hours, _fld_id
FROM "SD_PRJ".tbl_project p
JOIN "SD_PRJ".tbl_project_timesheet t USING (fld_id)
WHERE t.fld_project_id = p_project_id;
IF _sum_alloc_time <= _alloc_hours THEN
INSERT INTO "SD_PRJ".tbl_project_timesheet
(fld_emp_id, fld_project_id, fld_is_allocated, fld_allocated_time
, fld_achieved_time, fld_task_desc, fld_obs, fld_date)
VALUES (p_uid, p_project_id, coalesce(alloc_id,0), p_allocated_time
, p_achieved_time, p_task_desc, p_obs, p_date);
-- alloc_id is undefined, you probably need to use SELECT .. FROM .. instead
RAISE NOTICE 'INSERT OK!';
ELSE
RAISE NOTICE 'NOT OK';
END IF;
END
$func$ LANGUAGE plpgsql;
But this is still needlessly inefficient. Could be done in a single DML statement with data-modifying CTEs. Try a search for related questions.
You need to study the basics first.