Answers for "psql empty table"

delete all entries postgres

DELETE FROM tablename;

show database not empty tables postgres

select schemaname, relname, n_tup_ins from pg_stat_all_tables WHERE schemaname = 'public' ORDER BY n_tup_ins

postgres clear table

TRUNCATE [ TABLE ] [ ONLY ] name [ * ] [, ... ]
    [ RESTART IDENTITY | CONTINUE IDENTITY ] [ CASCADE | RESTRICT ]