Syntax error in declaration of PL/pgSQL function - postgresql

Question

Can anyone help me with this procedure? It's a pretty simple one, just want to insert some data into a table, but pgAdmin is giving me some errors.
This is the procedure code:
CREATE OR REPLACE FUNCTION FILL_INVOICE2(IN_NUM integer)
RETURNS void AS
DECLARE
counter numeric := 0;
BEGIN
IF in_num > 1 THEN
WHILE counter < 10
LOOP
INSERT INTO INVOICE(ID,INVOICE_ID,SUBSCRIBER_ID,AMOUNT,INVOICE_DATE,RECORD_DATE,INVOICE_TYPE,REST_TO_PAY,DESCRIPTION,INVOICE_REFERENCE)
VALUES(counter,counter,counter,100,current_date,current_date,1,100,'Telco services',1111);
counter := counter + 1;
RAISE NOTICE 'The counter is %', counter;
END LOOP;
END IF;
RETURN;
END;
Error is:
ERROR: syntax error at or near "DECLARE counter numeric"
LINE 3: DECLARE
^
********** Error **********
ERROR: syntax error at or near "DECLARE counter numeric"
SQL state: 42601
Character: 75"

Answer 1

This would work:
CREATE OR REPLACE FUNCTION fill_invoice2(in_num integer)
RETURNS void AS
$func$
DECLARE
counter numeric := 0;
BEGIN
IF in_num > 1 THEN
WHILE counter < 10
LOOP
INSERT INTO invoice(ID,INVOICE_ID,SUBSCRIBER_ID,AMOUNT,INVOICE_DATE,RECORD_DATE
,INVOICE_TYPE,REST_TO_PAY,DESCRIPTION,INVOICE_REFERENCE)
VALUES(counter,counter,counter,100,current_date,current_date
,1,100,'Telco services',1111);
counter := counter + 1;
RAISE NOTICE 'The counter is %', counter;
END LOOP;
END IF;
END
$func$ LANGUAGE plpgsql;
Major points
Missing language declaration.
Missing quotes around function body. Preferrably, use dollar-quoting - like #Eelke advised. Details:
Insert text with single quotes in PostgreSQL
But the whole function looks needlessly expensive.
Use a single INSERT based on generate_series() to replace the expensive loop with inserts per row. Optionally, you can wrap it in a function. Example with simple SQL function:
CREATE OR REPLACE FUNCTION fill_invoice2(in_num integer)
RETURNS void AS
$func$
INSERT INTO invoice(ID,INVOICE_ID,SUBSCRIBER_ID,AMOUNT,INVOICE_DATE,RECORD_DATE
,INVOICE_TYPE,REST_TO_PAY,DESCRIPTION,INVOICE_REFERENCE)
SELECT g,g,g,100,current_date,current_date,1,100,'Telco services',1111
FROM generate_series(0,10) g
WHERE $1 > 1;
$func$ LANGUAGE sql;
Does the same as your original.
I would also consider column defaults for some of your columns. For instance:
ALTER TABLE invoice
ALTER COLUMN invoice_date SET DEFAULT current_date
, ALTER COLUMN record_date SET DEFAULT current_date;
Details:
converting mysql scripts to postgresql script
Then just don't mention those column in the INSERT statement and defaults are filled in automatically.

Answer 2

The body should be passed as a string
CREATE OR REPLACE FUNCTION FILL_INVOICE2(IN_NUM integer) RETURNS void AS
$$
DECLARE
counter numeric := 0;
BEGIN
IF in_num > 1 THEN
WHILE counter < 10 LOOP
INSERT INTOI NVOICE(ID,INVOICE_ID,SUBSCRIBER_ID,AMOUNT,INVOICE_DATE,
RECORD_DATE,INVOICE_TYPE,REST_TO_PAY,DESCRIPTION,INVOICE_REFERENCE)
VALUES(counter,counter,counter,100,current_date,current_date,1,100,
'Telco services',1111);
counter := counter + 1;
RAISE NOTICE 'The counter is %', counter;
END LOOP;
END IF;
RETURN;
END;
$$
You can use $$ to mark the beginning en end of a multiline string.