SELECT tbl::TEXT, HASH(tbl::TEXT), MD5(tbl::TEXT) FROM tbl;

D create table tbl as (select 1 as a, 2 as b, 3 as c);
D select tbl::text, hash(tbl::text), md5(tbl::text) from tbl;
┌──────────────────────────┬────────────────────────────┬──────────────────────────────────┐
│   CAST(tbl AS VARCHAR)   │ hash(CAST(tbl AS VARCHAR)) │    md5(CAST(tbl AS VARCHAR))     │
│         varchar          │           uint64           │             varchar              │
├──────────────────────────┼────────────────────────────┼──────────────────────────────────┤
│ {'a': 1, 'b': 2, 'c': 3} │        6764392534128998287 │ e31681d6e7ab078c9679fcd4f50136eb │
└──────────────────────────┴────────────────────────────┴──────────────────────────────────┘

The text of rows can be aggregated and hashed to a single value, unknown if there are limits to how many rows (string size) this can support:

SELECT md5(string_agg(tbl::text, '')) FROM tbl;