how to prefix a string before sequence generated by postgresql?

database, postgresql, sequence

Solution

Here are a couple ways:

-- Referencing the sequence directly:
CREATE SEQUENCE test_seq;

SELECT 'AAAA'||nextval('test_seq')::TEXT;
 ?column? 
----------
 AAAA1

SELECT 'AAAA'||nextval('test_seq')::TEXT;
 ?column? 
----------
 AAAA2


-- Using a DEFAULT
CREATE TABLE abc 
    (val TEXT NOT NULL DEFAULT 'AAAA'||nextval('test_seq'::regclass)::TEXT, 
    foo TEXT);

INSERT INTO abc (foo) VALUES ('qewr');

SELECT * FROM abc;
  val  | foo  
-------+------
 AAAA3 | qewr

These assume that you have carefully decided how to proceed, based on the comments to your original question, as asked by the others.

Problem

This is a sequence ``` CREATE SEQUENCE technician_id_seq START WITH 1 INCREMENT BY 1 NO MINVALUE NO MAXVALUE CACHE 1; ``` It generates 1 2 3 4 I need the sequence as AAA1 AAA2 AAA3 AAA4 Is it possible? I am very much new to postgresql.

Original source