--- title: "Bitwise operators on BIT values" slug: "dev-database-reference-sql-functions-binary-hash-uuid-bitwise-operators-on-bit" updated: 2026-10-30T18:18:51Z published: 2026-10-30T18:18:51Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-binary-hash-uuid-bitwise-operators-on-bit" --- > ## 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. # Bitwise operators on BIT values *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) › Bit strings.* `&` (AND), `|` (OR), `xor()`, `~` (NOT) and the shifts `<<` and `>>` work on `BIT` values bit by bit, and return a `BIT` value of the same length: `'1100'::BIT & '1010'::BIT` is `'1000'`. The same operators on integers are on their own pages ([Similar functions](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-bitwise-operators-on-bit#similar-functions)). ## Syntax ``` a & b a | b xor(a, b) ~a a << n a >> n ``` | Argument | Type | Description | | --- | --- | --- | | `a`, `b` | `BIT` | The bit strings. `a` and `b` must have the same length. | | `n` | `INTEGER` | The number of positions to shift. | **Returns:** `BIT`, the same length as `a`. ## 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_binary_hash_uuid_bitwise_operators_on_bit`. 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 five feature-flag sets and a mask for each, stored as `VARCHAR` strings of 0s and 1s of the same length in each row. The third row has no values: ``` 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_binary_hash_uuid_bitwise_operators_on_bit"' 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}.flags" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, bits VARCHAR, mask VARCHAR)") run(f"INSERT INTO {TABLE} VALUES " "(1, '1011', '1100'), " "(2, '0', '1'), " "(3, NULL, NULL), " "(4, '10000000', '11111111'), " "(5, '0110', '0011')") ``` ``` [] [] [(5,)] ``` ## What it does Each operator works position by position: | Operator | Result bit is 1 when | `'1100'` with `'1010'` | | --- | --- | --- | | `a & b` (AND) | both bits are 1 | `'1000'` | | `a \| b` (OR) | either bit is 1 | `'1110'` | | `xor(a, b)` | exactly one bit is 1 | `'0110'` | | `~a` (NOT) | the bit of `a` is 0 | `~'1100'` is `'0011'` | | `a << n` | the bits move `n` places left; 0s come in on the right | `'1100' << 1` is `'1000'` | | `a >> n` | the bits move `n` places right; 0s come in on the left | `'1100' >> 1` is `'0110'` | The result always has the length of `a`: a shift drops the bits that move out, and a shift by the length or more gives all 0s. `xor` is a function, not an operator: `^` is the power operator and `#` isn't an operator. One operand can be a string literal of 0s and 1s when the other is a `BIT` value: `'1100' & '1010'::BIT` works. A `VARCHAR` column must be cast: `CAST(bits AS BIT)`. ## NULLs and edge cases | Input | Result | | --- | --- | | `'101'::BIT & NULL`, `NULL` `\|` `'101'::BIT`, `xor('101'::BIT, NULL)` | `NULL` | | `'1011'::BIT << NULL`, `NULL::BIT >> 1` | `NULL` | | `xor('1100'::BIT, '1100'::BIT)` | `'0000'` | | `'1100'::BIT << 4`, `'1100'::BIT >> 100` | `'0000'` | | `'1100'::BIT >> -1` | `'0000'` | | `'1100'::BIT << -1` | Error: `Cannot left-shift by negative number -1` | | `'1100'::BIT & '10'::BIT` | Error: `Cannot AND bit strings of different sizes` (`OR` and `XOR` likewise) | | `'1100' & '1010'` (two string literals) | Error: `Could not choose a best candidate function for the function call "&(STRING_LITERAL, STRING_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-binary-hash-uuid-bitwise-operators-on-bit#set-up-the-examples): ``` run("SELECT '101'::BIT & NULL, NULL | '101'::BIT, xor('101'::BIT, NULL), '1011'::BIT << NULL, NULL::BIT >> 1") run("SELECT CAST(xor('1100'::BIT, '1100'::BIT) AS VARCHAR), CAST('1100'::BIT << 4 AS VARCHAR), " "CAST('1100'::BIT >> 100 AS VARCHAR), CAST('1100'::BIT >> -1 AS VARCHAR)") run("SELECT CAST('1100'::BIT << -1 AS VARCHAR)") run("SELECT '1100'::BIT & '10'::BIT") run("SELECT '1100' & '1010'") ``` ``` [(None, None, None, None, None)] [('0000', '0000', '0000', '0000')] OSError: Cannot left-shift by negative number -1 OSError: Cannot AND bit strings of different sizes InternalError: Binder Error: Could not choose a best candidate function for the function call "&(STRING_LITERAL, STRING_LITERAL)". In order to select one, please add explicit type casts. ``` ## Examples Combine each row's flags with its mask. The operators return `BIT` values, so each is cast to `VARCHAR`: ``` run(f"SELECT id, bits, mask, " f"CAST(CAST(bits AS BIT) & CAST(mask AS BIT) AS VARCHAR), " f"CAST(CAST(bits AS BIT) | CAST(mask AS BIT) AS VARCHAR), " f"CAST(xor(CAST(bits AS BIT), CAST(mask AS BIT)) AS VARCHAR) " f"FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, '1011', '1100', '1000', '1111', '0111'), (2, '0', '1', '0', '1', '1'), (3, None, None, None, None, None), (4, '10000000', '11111111', '10000000', '11111111', '01111111'), (5, '0110', '0011', '0010', '0111', '0101')] ``` Invert and shift each row's flags: ``` run(f"SELECT id, bits, CAST(~CAST(bits AS BIT) AS VARCHAR), " f"CAST(CAST(bits AS BIT) << 2 AS VARCHAR), CAST(CAST(bits AS BIT) >> 2 AS VARCHAR) " f"FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, '1011', '0100', '1100', '0010'), (2, '0', '1', '0', '0'), (3, None, None, None, None), (4, '10000000', '01111111', '00000000', '00100000'), (5, '0110', '1001', '1000', '0001')] ``` Keep the rows that have at least one of their mask's flags set: ``` run(f"SELECT id, bits, mask FROM {TABLE} " f"WHERE bit_count(CAST(bits AS BIT) & CAST(mask AS BIT)) > 0 ORDER BY id LIMIT 10") ``` ``` [(1, '1011', '1100'), (4, '10000000', '11111111'), (5, '0110', '0011')] ``` ## 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`). VAST DataBase can evaluate a comparison of a column with a constant, but not an operator applied to a column, so these operators are always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the columns and the Query Engine computes the operator for each row it returns. - **In `WHERE`,** the scan sends the columns for every row, and a `FILTER` step in the Query Engine computes the operator and keeps the rows that match. No rows are skipped in storage. The plan of the `WHERE` example shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE bit_count(CAST(bits AS BIT) & CAST(mask AS BIT)) > 0") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #2 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (bit_count((CAST(bits AS │ │ BIT) & CAST(mask AS BIT))│ │ ) > 0) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ bits │ │ mask │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Compare stored strings when you test for one exact pattern.** `bits = '1011'` compares the raw `VARCHAR` column with a constant, so it's pushed down to VAST DataBase and rows that don't match never leave storage. The plan has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE bits = '1011'") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Store a flag you filter on often in its own column.** A `BOOLEAN` or integer column compared with a constant is pushed down; a mask test on a bit string isn't. - **Combine it with a pushed-down condition.** In `id > 100 AND bit_count(...) > 0`, `id > 100` is still evaluated in VAST DataBase, so the operators run only on the rows that pass it. ## Limitations and errors - **Same length only.** `&`, `|` and `xor` on bit strings of different lengths fail with `Cannot AND bit strings of different sizes` (or `OR`, `XOR`). Pad the shorter one with [bitstring](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-bitstring) first. ``` run("SELECT CAST(bitstring('10', 4) & '1110'::BIT AS VARCHAR)") ``` ``` [('0010',)] ``` - **No negative left shift.** `<< -1` fails with `Cannot left-shift by negative number -1`; `>> -1` returns all 0s. - **Don't mix `BIT` and integer operands.** `123 & '1100'::BIT` fails with `No function matches the given name and argument types '&(INTEGER_LITERAL, BIT)'`. Cast both to `BIT`, or both to integers. - **No `^` or `#` for XOR, and no `~~`.** `^` is the power operator and fails on `BIT` values with `No function matches the given name and argument types '^(BIT, BIT)'`; `#` is a syntax error. `~~` is a different operator, which takes two `VARCHAR` values, so `~~b` fails with `No function matches the given name and argument types '~~(BIT)'`. ``` run("SELECT '1100'::BIT ^ '1010'::BIT") run("SELECT CAST(~~'1100'::BIT AS VARCHAR)") ``` ``` InternalError: Binder Error: No function matches the given name and argument types '^(BIT, BIT)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types '~~(BIT)'. You might need to add explicit type casts. ``` - **`xor` isn't for booleans.** `xor(true, false)` fails with `No function matches the given name and argument types 'xor(BOOLEAN, BOOLEAN)'`. ## Similar functions The same operators work on integers, on their own pages. They return an integer: | Operator | On `'1100'::BIT` and `'1010'::BIT` | On `12` and `10` | | --- | --- | --- | | [& (bitwise AND)](/develop/docs/dev-database-reference-sql-functions-operators-bitwise-and) | `'1000'` | `8` | | [xor](/develop/docs/dev-database-reference-sql-functions-numeric-xor) | `'0110'` | `6` | | [~ (bitwise NOT)](/develop/docs/dev-database-reference-sql-functions-numeric-bitwise-not) | `'0011'` | `-13` | | [<< (shift left)](/develop/docs/dev-database-reference-sql-functions-operators-shift-left) by 1 | `'1000'` | `24` | | [>> (shift right)](/develop/docs/dev-database-reference-sql-functions-operators-shift-right) by 1 | `'0110'` | `6` | OR on integers is on [bitwise OR](/develop/docs/dev-database-reference-sql-functions-operators-bitwise-or). ``` run("SELECT CAST('1100'::BIT & '1010'::BIT AS VARCHAR), 12 & 10, CAST(xor('1100'::BIT, '1010'::BIT) AS VARCHAR), " "xor(12, 10), CAST(~'1100'::BIT AS VARCHAR), ~12") run("SELECT CAST('1100'::BIT << 1 AS VARCHAR), 12 << 1, CAST('1100'::BIT >> 1 AS VARCHAR), 12 >> 1") ``` ``` [('1000', 8, '0110', 6, '0011', -13)] [('1000', 24, '0110', 6)] ``` 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#bit-strings): all the bit string functions. - [BIT values and casts](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-bit-values), [bitstring](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-bitstring) and [bit_count](/develop/docs/dev-database-reference-sql-functions-binary-hash-uuid-bit-count). - [Where filters run](/develop/docs/dev-database-reference-sql-select#where-filters-run) and [pushdowns](/develop/docs/dev-database-reference-pushdowns).