Syntax error at CREATE TRIGGER query - postgresql

Question

I have this code, to add trigger for a View in my postgresql database
CREATE OR REPLACE FUNCTION changeCityProc() RETURNS TRIGGER AS $changeCity$
BEGIN
UPDATE vvs.tb_company SET city = "LAL" WHERE cardpresso.cardinfo.tb_company_city = vvs.tb_company.city;
RETURN null;
END;
$changeCity$ LANGUAGE plpgsql;
CREATE TRIGGER mytrigger
INSTEAD OF UPDATE ON
cardpresso.cardinfo FOR EACH ROW EXECUTE PROCEDURE changeCityProc();
pgAdmin says "syntax error at or near "INSTEAD""

Answer 1

Let's simplify this. First, the two schemas.
CREATE SCHEMA cardpresso;
CREATE SCHEMA vvs;
Next, the simplest possible table.
CREATE TABLE vvs.tb_company
(
city character varying(25)
);
INSERT INTO vvs.tb_company VALUES ('foo');
And a fairly useless view.
CREATE VIEW cardpresso.cardinfo AS
SELECT 'test' as tb_company_city UNION ALL
SELECT 'Orem' UNION ALL
SELECT 'Wibble'
;
Simplify the function. Warning: This will destructively update the table. Be careful if you copy stuff from this function into something headed for production.
CREATE OR REPLACE FUNCTION changecityproc()
RETURNS trigger AS
$BODY$
BEGIN
UPDATE vvs.tb_company SET city = 'bar';
RETURN null;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
Finally, the trigger.
CREATE TRIGGER mytrigger
INSTEAD OF UPDATE
ON cardpresso.cardinfo
FOR EACH ROW
EXECUTE PROCEDURE changecityproc();
Now, if we update the view, we'd expect all the rows in vvs.tb_company to change to 'bar'.
select * from vvs.tb_company;
city
--
foo
update cardpresso.cardinfo
set tb_company_city = 'wibble';
select * from vvs.tb_company;
city
--
bar
So it looks like the problem is in the UPDATE statement of your function.
UPDATE vvs.tb_company SET city = "LAL"
WHERE cardpresso.cardinfo.tb_company_city = vvs.tb_company.city;
I'm not certain what you intended that statement to do, but it's not valid in PostgreSQL, regardless of whether "LAL" is supposed to be a column name or a string literal. As a string literal, 'LAL', it will raise an error.
ERROR: missing FROM-clause entry for table "cardinfo"
LINE 2: WHERE cardpresso.cardinfo.tb_company_city = vvs.tb_compa...