PostgreSQL



Get 20 Largest Tables:
select
    n.nspname as "schema"
    , relname::text as "name"
    , pg_size_pretty(pg_total_relation_size(c.oid))::text as "total size"
    , c.reltuples::numeric as "rows"
from
    pg_class c
    left join pg_namespace n on n.oid = c.relnamespace
where
    (pg_total_relation_size(c.oid)>>20)>0 and c.relkind='r'
order by
    c.reltuples desc
limit 20;