Find replication lag in SQL without user defined functions

replication_lag.sql

with primary_server as (
  select split_part(x.full,'/',1) as xlog,
  split_part(x.full,'/',2) as offset
  from (select '88DC/113BBDA0'::text as full) x
),
standby_server as (
  select split_part(x.full,'/',1) as xlog,
  split_part(x.full,'/',2) as offset
  from (select '88DB/113BBDA0'::text as full) x
)
select
  (
    x'FF000000'::bigint
    * (format('x%s',lpad(primary_server.xlog,8,'0')))::bit(32)::bigint
    + (format('x%s',lpad(primary_server.offset,8,'0')))::bit(32)::bigint
  ) - (
    x'FF000000'::bigint
    * (format('x%s',lpad(standby_server.xlog,8,'0')))::bit(32)::bigint
    + (format('x%s',lpad(standby_server.offset,8,'0')))::bit(32)::bigint
  )
FROM primary_server, standby_server;