Getting row count for all the tables in Database

FUNCTION

CREATE OR REPLACE FUNCTION 
get_count(schema text, tablename text) RETURNS integer
AS
$body$
DECLARE
  count integer;
  query varchar;
BEGIN
  query := 'SELECT count(1) FROM ' || schema || '.' || tablename;
  EXECUTE query INTO count;
  RETURN count;
END;
$body$
LANGUAGE plpgsql;

Query to get count

Greenplum

SELECT
     n.nspname as "Schema",
     c.relname as "Table",
     get_count(n.nspname, c.relname)
FROM pg_catalog.pg_class c
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
AND c.relstorage != 'x'  -- excludes external tables
AND n.nspname not in ('pg_catalog','information_schema')
AND c.oid not in (SELECT inhrelid from pg_inherits)  --excludes child partition tables
ORDER BY 3 desc;

PostgreSQL

SELECT
     n.nspname as "Schema",
     c.relname as "Table",
     get_count(n.nspname, c.relname)
FROM pg_catalog.pg_class c
     JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind = 'r'
AND n.nspname not in ('pg_catalog','information_schema')
AND c.oid not in (SELECT inhrelid from pg_inherits)  --excludes child partition tables
ORDER BY 3 desc;

Result

Schema	Table	Row count
public	ttblsize	10416272
public	test_yogesh	11000
public	tdbsize	7129
public	reorg_history	190
public	vacuum_history	23
public	test11	20
public	test_after_upgrade	5
public	test_sravan	3
public	test12	1