jitscar

create or replace function 
count_rows(schema text, tablename text) returns integer
as
$body$
declare
  result integer;
  query varchar;
begin
  query := 'SELECT reltuples::bigint AS estimate FROM pg_class WHERE oid = to_regclass(''' || schema || '.' || tablename || ''')';
  execute query into result;

jitscar

do
$$
declare
  l_stmt text;
begin
  select 'TRUNCATE ' || string_agg(format('%I.%I', schemaname, tablename), ',')
    into l_stmt
  from pg_tables
  where schemaname in ('public', 'sources');