--- title: "translate" slug: "dev-database-reference-sql-functions-string-translate" updated: 2026-10-30T18:18:56Z published: 2026-10-30T18:18:56Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-string-translate" --- > ## 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. # translate *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) › Changing text.* Replaces single characters: each character of `from` found in the string becomes the character at the same position in `to`, or is removed if `to` has no character at that position. `translate` has no aliases. ## Syntax ``` translate(s, from, to) ``` | Argument | Type | Description | | --- | --- | --- | | `s` | `VARCHAR` | The string to change. | | `from` | `VARCHAR` | The characters to replace. | | `to` | `VARCHAR` | The replacement for each character of `from`, by position. | **Returns:** `VARCHAR`. **Aliases:** none. ## 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_translate`. 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 four contacts with phone numbers written in different styles. The last 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_translate"' 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}.contacts" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, name VARCHAR, phone VARCHAR)") run(f"INSERT INTO {TABLE} VALUES " "(1, 'Ada Lovelace', '+44 20 7946 0018'), " "(2, 'Grace Hopper', '+1 (555) 010-2368'), " "(3, 'José Martí', '+53 7-555-0142'), " "(4, NULL, NULL)") ``` ``` [] [] [(4,)] ``` ## What it does `translate` reads `from` and `to` as two lists of characters and pairs them by position: the first character of `from` with the first of `to`, and so on. Each character of `s` that appears in `from` is replaced by its partner in `to`; the other characters are copied unchanged. | Call | Result | Why | | --- | --- | --- | | `translate('Hello', 'el', 'EL')` | `'HELLo'` | `e` becomes `E` and every `l` becomes `L`. | | `translate('abc', 'abc', 'x')` | `'x'` | `a` becomes `x`; `b` and `c` have no partner in `to`, so they're removed. | | `translate('a-b_c', '-_', '')` | `'abc'` | With an empty `to`, every character of `from` is removed. | | `translate('abc', 'a', 'xyz')` | `'xbc'` | Extra characters in `to` are ignored. | | `translate('aaa', 'aa', 'xy')` | `'xxx'` | A character listed twice in `from` uses its first partner. | | `translate('abc', '', 'x')` | `'abc'` | An empty `from` changes nothing. | | `translate('Hello', 'h', 'X')` | `'Hello'` | The match is case-sensitive: `h` doesn't match `H`. | | `translate('café', 'é', 'e')` | `'cafe'` | Characters outside ASCII are translated like any other. | | `translate('Łódź ø', 'Łø', 'Lo')` | `'Lódź o'` | Only the characters listed in `from` change; `ó` and `ź` are copied as they are. | `translate` works on Unicode code points, not on what a reader sees as one character. In `'e\u0301'` (an `e` followed by the combining accent U+0301, displayed as é), the `e` is translated and the accent stays, so translating `e` to `E` gives É. For the same reason, a precomposed `é` (U+00E9) in `from` doesn't match `e` followed by U+0301 in `s`: that text is returned unchanged. See [length](/develop/docs/dev-database-reference-sql-functions-string-length) for code points. ``` run("SELECT translate('e\u0301', 'el', 'EL') = 'E\u0301', length(translate('e\u0301', 'el', 'EL'))") ``` ``` [(True, 2)] ``` To replace a substring of several characters as a whole, use [replace](/develop/docs/dev-database-reference-sql-functions-string-replace). ## NULLs and edge cases | Input | Call | Result | | --- | --- | --- | | `s` is `NULL` | `translate(NULL, 'el', 'EL')` | `NULL` | | `from` is `NULL` | `translate('abc', NULL, 'x')` | `NULL` | | `to` is `NULL` | `translate('abc', 'a', NULL)` | `NULL` | | `''` (empty string) | `translate('', 'el', 'EL')` | `''` | | `from` is `''` | `translate('abc', '', 'x')` | `'abc'`, unchanged | | `to` is `''` | `translate('a-b_c', '-_', '')` | `'abc'`: every character of `from` removed | | `to` shorter than `from` | `translate('abc', 'abc', 'x')` | `'x'`: `b` and `c` have no partner and are removed | | `to` longer than `from` | `translate('abc', 'a', 'xyz')` | `'xbc'`: the extra characters are ignored | | A character twice in `from` | `translate('aaa', 'aa', 'xy')` | `'xxx'`: the first partner wins | | A character outside ASCII | `translate('café', 'é', 'e')` | `'cafe'` | | A number as `s` | `translate(123, 'el', 'EL')` | Error: `No function matches the given name and argument types` | | A `BLOB` as `s` | `translate('\xAA'::BLOB, 'el', 'EL')` | 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-translate#set-up-the-examples): ``` run("SELECT translate(NULL, 'el', 'EL'), translate('abc', NULL, 'x'), translate('abc', 'a', NULL), translate('', 'el', 'EL')") run("SELECT translate('abc', '', 'x'), translate('a-b_c', '-_', ''), translate('abc', 'abc', 'x'), translate('abc', 'a', 'xyz'), translate('aaa', 'aa', 'xy'), translate('café', 'é', 'e')") run("SELECT translate(123, 'el', 'EL')") run("SELECT translate('\\xAA'::BLOB, 'el', 'EL')") ``` ``` [(None, None, None, '')] [('abc', 'abc', 'x', 'xbc', 'xxx', 'cafe')] InternalError: Binder Error: No function matches the given name and argument types 'translate(INTEGER_LITERAL, STRING_LITERAL, STRING_LITERAL)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'translate(BLOB, STRING_LITERAL, STRING_LITERAL)'. You might need to add explicit type casts. ``` ## Examples Remove the spaces, brackets and hyphens from each phone number. `to` is empty, so every character of `from` is removed: ``` run(f"SELECT id, translate(phone, ' ()-', '') FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, '+442079460018'), (2, '+15550102368'), (3, '+5375550142'), (4, None)] ``` Replace accented vowels with plain ones, character by character. `from` and `to` have the same length, so each accented vowel has a partner: ``` run(f"SELECT id, translate(name, 'áéíóú', 'aeiou') FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 'Ada Lovelace'), (2, 'Grace Hopper'), (3, 'Jose Marti'), (4, None)] ``` Find a contact by phone number, whatever punctuation it was stored with: ``` run(f"SELECT id, name FROM {TABLE} WHERE translate(phone, ' ()-', '') = '+15550102368' ORDER BY id LIMIT 10") ``` ``` [(2, 'Grace Hopper')] ``` ## 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 `translate()` is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `translate()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `translate()` 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 translate(phone, ' ()-', '') = '+15550102368'") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (translate(phone, ' ()-', │ │ '') = '+15550102368') │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ phone │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Store the cleaned value if you filter on it often.** Apply `translate()` when you write the rows, keep the result in its own column, and compare that column with a constant. The comparison is pushed down to VAST DataBase, so rows that don't match never leave storage. The plan for `phone = '+44 20 7946 0018'` has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE phone = '+44 20 7946 0018'") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Combine it with a pushed-down condition.** In `id > 100 AND translate(phone, ' ()-', '') = '...'`, `id > 100` is still evaluated in VAST DataBase, so `translate()` 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 a value to `VARCHAR` first. - **One character for one character.** A character of `from` can't become two characters, and a group of characters can't be matched as a whole. Use [replace](/develop/docs/dev-database-reference-sql-functions-string-replace) for substrings and [regexp_replace](/develop/docs/dev-database-reference-sql-functions-string-regexp-replace) for patterns. - **Case-sensitive.** `translate('Hello', 'h', 'X')` changes nothing. List both cases in `from` if you need both. - **Code points, not characters.** An accent written as a separate combining character isn't part of the letter before it, and a precomposed `é` in `from` doesn't match `e` followed by U+0301. See [What it does](/develop/docs/dev-database-reference-sql-functions-string-translate#what-it-does). To remove accents without listing them, use [strip_accents](/develop/docs/dev-database-reference-sql-functions-string-strip-accents). ``` run("SELECT translate(DATE '2026-10-16', '-', '/')") ``` ``` InternalError: Binder Error: No function matches the given name and argument types 'translate(DATE, STRING_LITERAL, STRING_LITERAL)'. You might need to add explicit type casts. ``` ## Similar functions | Function | What it replaces | Call | Result | | --- | --- | --- | --- | | `translate` | single characters: `a` becomes `x`, and `b`, which has no partner, is removed | `translate('abcabc', 'ab', 'x')` | `'xcxc'` | | [replace](/develop/docs/dev-database-reference-sql-functions-string-replace) | each occurrence of the substring `'ab'` | `replace('abcabc', 'ab', 'x')` | `'xcxc'` | | [regexp_replace](/develop/docs/dev-database-reference-sql-functions-string-regexp-replace) | matches of a regular expression, here with the `'g'` option | `regexp_replace('abcabc', 'ab', 'x', 'g')` | `'xcxc'` | | `translate` | each `a` (the second `a` in `from` is ignored) | `translate('aaa', 'aa', 'xy')` | `'xxx'` | | [replace](/develop/docs/dev-database-reference-sql-functions-string-replace) | `'aa'`, without overlaps | `replace('aaa', 'aa', 'b')` | `'ba'` | | [strip_accents](/develop/docs/dev-database-reference-sql-functions-string-strip-accents) | accents, removed from every letter | `strip_accents('Crème')` | `'Creme'` | ``` run("SELECT translate('abcabc', 'ab', 'x'), replace('abcabc', 'ab', 'x'), regexp_replace('abcabc', 'ab', 'x', 'g')") run("SELECT translate('aaa', 'aa', 'xy'), replace('aaa', 'aa', 'b'), strip_accents('Crème')") ``` ``` [('xcxc', 'xcxc', 'xcxc')] [('xxx', 'ba', 'Creme')] ``` 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. - [replace](/develop/docs/dev-database-reference-sql-functions-string-replace) and [strip_accents](/develop/docs/dev-database-reference-sql-functions-string-strip-accents). - [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.