--- title: "from_binary" slug: "dev-database-reference-sql-functions-string-from-binary" updated: 2026-10-30T18:18:56Z published: 2026-10-30T18:18:56Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-string-from-binary" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt > Use this file to discover all available pages before exploring further. # from_binary *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Binary, hash and UUID functions](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid) › Binary text.* Reads a string of `0`s and `1`s and returns the bytes it describes, as a `BLOB`. It's the reverse of [bin](/develop/docs/dev-database-reference-sql-functions-string-bin). `unbin` is the same function. ## Syntax ``` from_binary(s) unbin(s) ``` | Argument | Type | Description | | --- | --- | --- | | `s` | `VARCHAR` | Binary digits: only `0` and `1`, most significant bit first. | **Returns:** `BLOB`. **Aliases:** `unbin`. ## Set up the examples The examples connect with the ADBC driver, as in [VAST Query Engine (ADBC)](/develop/docs/dev-database-integrations-adbc), and work in a schema called `docs_sql_fn_string_from_binary`. Set `QE_ENDPOINT`, `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY` and `VASTDB_BUCKET` ([SQL reference](/develop/docs/dev-database-reference-sql-index#example-connect-and-use-a-transaction)), and run the blocks in order in one Python session. Below each block is the output you should see. This block connects, defines the `run()` and `plan()` helpers, and creates a table of bit strings. The last row has no value: ``` import os import re import adbc_driver_manager import adbc_driver_manager.dbapi as dbapi import adbc_driver_vastdb BUCKET = os.environ["VASTDB_BUCKET"] SCHEMA = f'"{BUCKET}/docs_sql_fn_string_from_binary"' conn = dbapi.connect( driver=adbc_driver_vastdb.get_driver_path(), db_kwargs={ "vast.db.endpoint": os.environ["QE_ENDPOINT"], "vast.db.access_key": os.environ["AWS_ACCESS_KEY_ID"], "vast.db.secret_key": os.environ["AWS_SECRET_ACCESS_KEY"], }, autocommit=True, ) def server_message(e): """The server's message in a driver error, without the request ID or the echoed statement.""" text = re.sub(r"\[req=0x[0-9a-f]+\]: ", "", str(e)) found = (re.search(r'message: "(.*?)", request_id', text, re.S) or re.search(r"description: (.*)\)", text, re.S)) message = found.group(1) if found else text.strip().splitlines()[-1] message = re.sub(r"^Plan query: '.*?' failed with: ", "", message, flags=re.S) message = re.split(r"\\n|\n", message)[0].replace('\\"', '"') return message.replace(BUCKET, "") def run(sql): """Run one statement. Print the rows it returns, or the error.""" try: with conn.cursor() as cur: cur.execute(sql) rows = cur.fetchall() if cur.description else [] except (adbc_driver_manager.Error, OSError) as e: print(f"{type(e).__name__}: {server_message(e)}") else: print(rows) def plan(sql): """Print the plan without its ~N Rows lines: the table's row count, which can still be 0 just after an insert.""" with conn.cursor() as cur: cur.execute("EXPLAIN " + sql) steps = cur.fetchall()[0][1] print("\n".join(line for line in steps.splitlines() if "Rows" not in line)) TABLE = f"{SCHEMA}.bits" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, b VARCHAR)") run(f"INSERT INTO {TABLE} VALUES " "(1, '01100001'), " "(2, '0110100001101001'), " "(3, '0110'), " "(4, '101010101'), " "(5, ''), " "(6, NULL)") ``` ``` [] [] [(6,)] ``` ## What it does `from_binary` reads the digits eight at a time and returns one byte for each group. If the number of digits isn't a multiple of eight, it's padded on the left with zeros to whole bytes, so the digits keep their value: | Input | Digits | Bytes | Result | | --- | --- | --- | --- | | `'01100001'` | 8 | 1 | `b'a'` | | `'0110'` | 4 | 1 | `b'\x06'` | | `'101010101'` | 9 | 2 | `b'\x01U'` (`0x01`, `0x55`) | The result is a `BLOB`, which the Python driver returns as `bytes`. To turn bytes that hold UTF-8 text back into a `VARCHAR`, use [decode](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-decode): `decode(from_binary(bin('café')))` is `'café'`. ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL` | `NULL` | | `''` (empty string) | `b''`, an empty `BLOB` | | `'0'`, `'1'` | One byte: `b'\x00'`, `b'\x01'` | | `'111111111'` (9 digits) | Two bytes | | `'012'`, `'x'` | Error: `Invalid input for binary digit: 2` (or `x`) | | `'0110 0001'` (a space) | Error: `Invalid input for binary digit:`, then the space | | `'0b0110'` (a prefix) | Error: `Invalid input for binary digit: b` | | A number, such as `1010` | Error: `No function matches the given name and argument types 'from_binary(INTEGER_LITERAL)'` | The same cases, as the cluster returns them. They use the table and helpers from [Set up the examples](/develop/docs/dev-database-reference-sql-functions-string-from-binary#set-up-the-examples): ``` run("SELECT from_binary(NULL), from_binary(''), from_binary('0'), from_binary('1'), " "octet_length(from_binary('111111111')), unbin('01100001')") run("SELECT from_binary('012')") run("SELECT from_binary('0110 0001')") run("SELECT from_binary('0b0110')") run("SELECT from_binary(1010)") ``` ``` [(None, b'', b'\x00', b'\x01', 2, b'a')] OSError: Invalid input for binary digit: 2 OSError: Invalid input for binary digit: OSError: Invalid input for binary digit: b InternalError: Binder Error: No function matches the given name and argument types 'from_binary(INTEGER_LITERAL)'. You might need to add explicit type casts. ``` ## Examples Each bit string as bytes, and the number of bytes: ``` run(f"SELECT id, b, from_binary(b), unbin(b), octet_length(from_binary(b)) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, '01100001', b'a', b'a', 1), (2, '0110100001101001', b'hi', b'hi', 2), (3, '0110', b'\x06', b'\x06', 1), (4, '101010101', b'\x01U', b'\x01U', 2), (5, '', b'', b'', 0), (6, None, None, None, None)] ``` A round trip through [bin](/develop/docs/dev-database-reference-sql-functions-string-bin): the bytes of a string, and the string again: ``` run("SELECT from_binary(bin('hi')), decode(from_binary(bin('caf\u00e9'))), from_binary(bin(5))") ``` ``` [(b'hi', 'café', b'\x05')] ``` Keep the rows that make exactly one byte: ``` run(f"SELECT id, b FROM {TABLE} WHERE octet_length(from_binary(b)) = 1 ORDER BY id LIMIT 10") ``` ``` [(1, '01100001'), (3, '0110')] ``` ## How it runs in VAST The Query Engine runs on the cluster's CNodes, and a query on a table starts with a scan in VAST DataBase (`VAST_SCAN`). `from_binary()` is a function of a column, so it's computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `from_binary()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `from_binary()` and keeps the rows that match. The plan of the `WHERE` example shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE octet_length(from_binary(b)) = 1") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (octet_length(from_binary │ │ (b)) = 1) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ b │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Store bytes as a `BLOB`, not as digits.** A `BLOB` column takes an eighth of the space of its digits, and needs no conversion when you read it. - **Combine it with a pushed-down condition.** In `id > 100 AND octet_length(from_binary(b)) = 1`, `id > 100` can be evaluated in VAST DataBase, so `from_binary()` runs only on the rows that pass it. See [pushdowns](/develop/docs/dev-database-reference-pushdowns). ## Limitations and errors - **Only `0` and `1`.** Any other character, including a space or a `0b` prefix, stops the query with an `OSError`: `Invalid input for binary digit: <character>`. Clean the digits first, for example with [replace](/develop/docs/dev-database-reference-sql-functions-string-replace) to remove spaces. - **`VARCHAR` only.** A number fails with `No function matches the given name and argument types`; write the digits as a string (`'1010'`), or use [bin](/develop/docs/dev-database-reference-sql-functions-string-bin) to make them. ## Similar functions | Function | Reads | Result for the byte `a` | | --- | --- | --- | | `from_binary`, `unbin` | Base-2 digits | `from_binary('01100001')` is `b'a'` | | [from_hex](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-from-hex) | Base-16 digits | `from_hex('61')` is `b'a'` | | [bin](/develop/docs/dev-database-reference-sql-functions-string-bin), `to_binary` | The reverse: bytes or an integer to digits | `bin('a')` is `'01100001'` | ``` run("SELECT from_binary('01100001'), unbin('01100001'), from_hex('61'), bin('a'), to_binary('a')") ``` ``` [(b'a', b'a', b'a', '01100001', '01100001')] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [Binary, hash and UUID functions](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid): all the binary and encoding functions. - [Where filters run](/develop/docs/dev-database-reference-sql-select#where-filters-run) and [pushdowns](/develop/docs/dev-database-reference-pushdowns). - [EXPLAIN](/develop/docs/dev-database-reference-sql-explain): how to read a plan.