create a new column with passwords using crypt

Question

I am currently trying to create a new column with passwords based on other column from the same table (tb_customer). The source to create the passwords is the column cust_cif.

The script I used is as follows:

ALTER TABLE erp.tb_customer 
  ADD COLUMN password CHAR (34) USING crypt(erp.tb_customer.cust_cif, gen_salt('md5'));

I am getting an error and don't know why, since md5 doesn't need installation (but I did nevertheless).

The error is the following:

ERROR:  does not exist type «crypt»
LINE 2:   ADD COLUMN password crypt(erp.tb_customer.cust_cif, gen_sa...

I also tried with

ALTER TABLE erp.tb_customer 
  ADD COLUMN password SELECT crypt(erp.tb_customer.cust_cif, gen_salt('md5'));

Here are some values shown in the table tb_customer:

cust_no | cust_name | cust_cif | last_updated_by | last_updated_date

"C0001" "PIENSOS MARTIN"    "A12345678" "SYSTEM"    "2022-04-28"
"C0002" "AGRICULTURA VIVES" "A66666666" "SYSTEM"    "2022-04-28"
"C0003" "CULTIVOS MARAVILLA"    "A55555555" "SYSTEM"    "2022-04-28"
"C0004" "ASOCIADOS PEREZ"   "A23126743" "SYSTEM"    "2022-04-28"
"C0005" "TECNICOS AVA"  "B34211233" "SYSTEM"    "2022-04-28"
"C0006" "AGR AGRI"  "B78788999" "SYSTEM"    "2022-04-28"
"C0007" "AGRIMARCOS"    "B98766562" "SYSTEM"    "2022-04-28"
"C0008" "CULTIVANDO ALEGRIA"    "B12333123" "SYSTEM"    "2022-04-28"
"C0009" "MARCOS LIMPIEZA"   "A87727711" "SYSTEM"    "2022-04-28"
"C0010" "VIAJES MUNDO"  "A00099982" "SYSTEM"    "2022-04-28"

What am I doing wrong?

Thank you in advance.

Answer 1

There is no ADD COLUMN...USING.

You will have to add the column and populate it (UPDATE) in different statements. Possibly in the same transaction.

Answer 2

I would do it this way:

ALTER TABLE erp.tb_customer 
ADD COLUMN password_cryp char(100);

--CREATE EXTENSION pgcrypto;

CREATE OR REPLACE PROCEDURE erp.col_cryp() AS $$
DECLARE
  _row record;
BEGIN
    FOR _row IN (
        SELECT cust_cif FROM erp.tb_customer
        )
    LOOP
        UPDATE erp.tb_customer
        SET password_cryp = crypt('cust_cif', gen_salt('md5'));
    END LOOP;
END;
$$LANGUAGE plpgsql;

CALL erp.col_cryp();

To test it you can try:

SELECT ("password_cryp " = 'copy here the generated code on the table') AS IsMatch FROM erp.tb_customer;

Hope it works!