EAN13 barcode generator example plpgsql postgres

ean13_generator.sql

with recursive source as (
    select (220000000000::bigint + round(random() * 10000000000))::bigint as code
    from generate_series(1, 10000)
),
checksum_calc as (
    select code, 3 as cs_mult, 0::bigint as checksum, code as interm_code from source
    union
    select
        code,
        (case when cs_mult = 3 then 1 else 3 end) as cs_mult,
        interm_code % 10 * cs_mult as checksum,
        interm_code / 10 as interm_code
    from checksum_calc
    where interm_code > 0
)
select (code::text || ((10 - sum(checksum) % 10) % 10)::text)::bigint as code
from checksum_calc group by code