--- title: "ord" slug: "dev-database-reference-sql-functions-string-ord" updated: 2026-10-30T18:18:56Z published: 2026-10-30T18:18:56Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-string-ord" --- > ## 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. # ord *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Text basics](/develop/docs/dev-database-reference-sql-functions-string-text-basics) › Characters and code points.* Returns the Unicode code point of the first character of a string, as an integer, or -1 for an empty string. `unicode` is the same function. ## Syntax ``` ord(s) unicode(s) ``` | Argument | Type | Description | | --- | --- | --- | | `s` | `VARCHAR` | The string whose first character to read. | **Returns:** `INTEGER`. **Aliases:** `unicode`. ## 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_ord`. 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 labels: one in ASCII, one that starts with an accented letter, one that starts with a symbol, an empty label and a `NULL`: ``` 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_ord"' 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}.labels" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, label VARCHAR)") run(f"INSERT INTO {TABLE} VALUES " "(1, 'Invoice'), " "(2, 'Échéance'), " "(3, '€ amount'), " "(4, ''), " "(5, NULL)") ``` ``` [] [] [(5,)] ``` ## What it does `ord` returns the code point of the first character of `s`: the number that Unicode gives that character. For an empty string, which has no first character, it returns -1. | Call | Result | Why | | --- | --- | --- | | `ord('A')` | `65` | The code point of `A`, U+0041. | | `ord('Hello')` | `72` | Only the first character counts: `H`. | | `ord('AB')` | `65` | The same: `A`. | | `unicode('é')` | `233` | U+00E9, the precomposed é. | | `ord('€')` | `8364` | U+20AC. | | `unicode('😀')` | `128512` | U+1F600, a character outside the Basic Multilingual Plane. | | `ord('🇫🇷')` | `127467` | A flag is two code points; this is the first, U+1F1EB. | | `ord('')` | `-1` | An empty string has no first character. | A code point isn't always what a reader sees as the first character. The French flag is two regional-indicator code points, and `'e\u0301'` (displayed as é) is an `e` followed by a combining accent, so `ord` returns 101, the code of `e`. See [length](/develop/docs/dev-database-reference-sql-functions-string-length) for code points and graphemes. ### How ord differs from ascii [ascii](/develop/docs/dev-database-reference-sql-functions-string-ascii) takes the same argument and, for each non-empty string on this page, returns the same code point as `ord`. The difference is the empty string: | Input | `ord` and `unicode` | `ascii` | | --- | --- | --- | | `''` | `-1` | `0` | | Any other string | its first code point | its first code point | -1 can't be a code point, so `ord(s) = -1` means that `s` is empty. The 0 that `ascii` returns for an empty string is also the code point of the NUL character, `chr(0)`. Use `ord` when you need to tell the two apart. ## NULLs and edge cases | Input | Call | Result | | --- | --- | --- | | `NULL` | `ord(NULL)` | `NULL` | | `''` (empty string) | `ord('')`, `unicode('')` | `-1` | | An ASCII character | `ord('A')` | `65` | | A character outside Latin-1 | `ord('€')` | `8364` | | A precomposed `é` (U+00E9) | `unicode('é')` | `233` | | A character outside the Basic Multilingual Plane | `unicode('😀')` | `128512` | | `e` followed by U+0301 | `ord('e\u0301')` | `101`, the code point of `e` | | A flag emoji | `ord('🇫🇷')` | `127467`, the first of its two code points | | A number | `ord(123)` | Error: `No function matches the given name and argument types` | | A `BLOB` | `unicode('\xAA'::BLOB)` | Error: `No function matches the given name and argument types` | 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-ord#set-up-the-examples): ``` run("SELECT ord(NULL), ord(''), unicode(''), ord('A'), ord('€'), unicode('é'), unicode('😀')") run("SELECT ord('e\u0301'), ord('🇫🇷')") run("SELECT ord(123)") run("SELECT unicode('\\xAA'::BLOB)") ``` ``` [(None, -1, -1, 65, 8364, 233, 128512)] [(101, 127467)] InternalError: Binder Error: No function matches the given name and argument types 'ord(INTEGER_LITERAL)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'unicode(BLOB)'. You might need to add explicit type casts. ``` ## Examples The first code point of each label, with `ord` and `unicode`, and with `ascii` for comparison. They differ only on the empty label: ``` run(f"SELECT id, label, ord(label), unicode(label), ascii(label) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 'Invoice', 73, 73, 73), (2, 'Échéance', 201, 201, 201), (3, '€ amount', 8364, 8364, 8364), (4, '', -1, -1, 0), (5, None, None, None, None)] ``` Keep the labels that start with a character outside ASCII. The empty label gives -1, so it isn't kept: ``` run(f"SELECT id, label FROM {TABLE} WHERE ord(label) > 127 ORDER BY id LIMIT 10") ``` ``` [(2, 'Échéance'), (3, '€ amount')] ``` Show the first code point in the usual U+ notation, with [printf](/develop/docs/dev-database-reference-sql-functions-string-printf). `%04X` is upper-case hexadecimal, at least four digits: ``` run(f"SELECT id, printf('U+%04X', ord(label)) FROM {TABLE} WHERE ord(label) >= 0 ORDER BY id LIMIT 10") ``` ``` [(1, 'U+0049'), (2, 'U+00C9'), (3, 'U+20AC')] ``` ## 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 a function of a column, so `ord()` is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `ord()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `ord()` and keeps the rows that match. No rows are skipped in storage. The plan of the first `WHERE` example shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE ord(label) > 127") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (ord(label) > 127) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ label │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Test for empty strings with `= ''`, not `ord(s) = -1`.** A comparison of the raw column with a constant is pushed down to VAST DataBase, so rows that don't match never leave storage. The plan for `label = ''` has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE label = ''") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Store the first code point if you filter on it often.** Compute `ord(label)` when you write the rows and keep it in its own column: `first_code > 127` is pushed down, `ord(label) > 127` isn't. - **Combine it with a pushed-down condition.** In `id > 100 AND ord(label) > 127`, `id > 100` is still evaluated in VAST DataBase, so `ord()` runs only on the rows that pass it. ## Limitations and errors - **Strings only.** A number, a decimal, a `BLOB`, a date, a boolean or a list fails with `No function matches the given name and argument types`. Cast it to `VARCHAR` first. - **The first code point, not the first character a reader sees.** A flag or a letter with a combining accent starts with a code point that isn't the whole character. See [What it does](/develop/docs/dev-database-reference-sql-functions-string-ord#what-it-does). - **-1 for an empty string,** where [ascii](/develop/docs/dev-database-reference-sql-functions-string-ascii) returns 0. Check for -1 before you pass the result to [chr](/develop/docs/dev-database-reference-sql-functions-string-chr): `chr(-1)` fails with `Invalid UTF8 Codepoint -1`. ``` run("SELECT ord(DATE '2026-10-16')") run("SELECT chr(ord(''))") ``` ``` InternalError: Binder Error: No function matches the given name and argument types 'ord(DATE)'. You might need to add explicit type casts. OSError: Invalid UTF8 Codepoint -1 ``` ## Similar functions | Function | Returns | `'Hello'` | `'é'` | `'e\u0301'` | `''` | | --- | --- | --- | --- | --- | --- | | `ord` | the first code point; -1 for an empty string | `72` | `233` | `101` | `-1` | | `unicode` | the same as `ord` | `72` | `233` | `101` | `-1` | | [ascii](/develop/docs/dev-database-reference-sql-functions-string-ascii) | the first code point; 0 for an empty string | `72` | `233` | `101` | `0` | | [chr](/develop/docs/dev-database-reference-sql-functions-string-chr) | the reverse: the character for a code point | | `chr(233)` is `'é'` | | | The last block also shows the NUL character, `chr(0)`: `ord` and `ascii` both return `0` for it. Only `ord` and `unicode` then give a different value, -1, for an empty string. ``` run("SELECT ord('Hello'), unicode('Hello'), ascii('Hello')") run("SELECT ord('é'), unicode('é'), ascii('é'), chr(233)") run("SELECT ord('e\u0301'), unicode('e\u0301'), ascii('e\u0301')") run("SELECT ord(''), unicode(''), ascii(''), ord(chr(0)), ascii(chr(0))") ``` ``` [(72, 72, 72)] [(233, 233, 233, 'é')] [(101, 101, 101)] [(-1, -1, 0, 0, 0)] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [Text basics](/develop/docs/dev-database-reference-sql-functions-string-text-basics): all the text functions. - [ascii](/develop/docs/dev-database-reference-sql-functions-string-ascii) and [chr](/develop/docs/dev-database-reference-sql-functions-string-chr). - [length](/develop/docs/dev-database-reference-sql-functions-string-length): code points and graphemes. - [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.