--- title: "isfinite" slug: "dev-database-reference-sql-functions-date-time-isfinite" updated: 2026-10-30T18:19:01Z published: 2026-10-30T18:19:01Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-date-time-isfinite" --- > ## 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. # isfinite *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Date and time functions](/develop/docs/dev-database-reference-sql-functions-date-time) › Special values.* Returns `true` if a date or timestamp is an ordinary value, and `false` if it's one of the special values `'infinity'` or `'-infinity'`. It's the opposite of [isinf](/develop/docs/dev-database-reference-sql-functions-date-time-isinf). ## Syntax ``` isfinite(value) ``` | Argument | Type | Description | | --- | --- | --- | | `value` | `DATE`, `TIMESTAMP` (also `TIMESTAMP_NS`, `TIMESTAMP_MS`, `TIMESTAMP_S`) or `TIMESTAMP WITH TIME ZONE` | The value to test. | **Returns:** `BOOLEAN`. `isfinite` also takes a `FLOAT` or `DOUBLE`; see [isfinite for numbers](/develop/docs/dev-database-reference-sql-functions-numeric-isfinite). ## 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_date_time_isfinite`. 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 events. Each has a date (`d`), a timestamp (`ts`), a time of day (`t`) and a timestamp with nanoseconds (`tns`). Row 4 has no values, and row 5 is the last moment of 1969: ``` 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_date_time_isfinite"' 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}.events" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, d DATE, ts TIMESTAMP, t TIME, tns TIMESTAMP_NS)") run(f"INSERT INTO {TABLE} VALUES " "(1, DATE '2026-02-28', TIMESTAMP '2026-02-28 23:15:00', TIME '23:15:00', " "CAST('2026-02-28 23:15:00.123456789' AS TIMESTAMP_NS)), " "(2, DATE '2026-03-01', TIMESTAMP '2026-03-01 08:30:45.123456', TIME '08:30:45.123456', " "CAST('2026-03-01 08:30:45.123456' AS TIMESTAMP_NS)), " "(3, DATE '2024-12-30', TIMESTAMP '2024-12-30 12:00:00', TIME '12:00:00', " "CAST('2024-12-30 12:00:00' AS TIMESTAMP_NS)), " "(4, NULL, NULL, NULL, NULL), " "(5, DATE '1969-12-31', TIMESTAMP '1969-12-31 23:59:59.999999', TIME '23:59:59.999999', " "CAST('1969-12-31 23:59:59.999999999' AS TIMESTAMP_NS))") ``` ``` [] [] [(5,)] ``` ## What it does A `DATE` or timestamp can hold two special values besides ordinary dates: `'infinity'`, later than every date, and `'-infinity'`, earlier than every date. Write them as `DATE 'infinity'`, `TIMESTAMP '-infinity'` and so on. `isfinite` returns `true` for every ordinary value, however far in the past or future (`isfinite(DATE '0001-01-01')` and `isfinite(DATE '9999-12-31')` are `true`), and `false` for either special value. It works the same on every timestamp precision and on a `TIMESTAMP WITH TIME ZONE`. For a non-NULL value, `isfinite(v)` is always `NOT isinf(v)`. Most date and time functions return `NULL` for a special value (for example, `year(DATE 'infinity')`), so use `isfinite` to keep only the values they can work on. ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL`, or a NULL value (row 4) | `NULL` | | `DATE 'infinity'`, `DATE '-infinity'` | `false` | | `TIMESTAMP 'infinity'`, `TIMESTAMP '-infinity'` | `false` | | `CAST('infinity' AS TIMESTAMP_NS)`, `TIMESTAMPTZ 'infinity'` | `false` | | `DATE '0001-01-01'`, `DATE '9999-12-31'`, 44 BC | `true` | | A `TIME` | Error: `No function matches the given name and argument types 'isfinite(TIME)'` | | An `INTERVAL` | Error: `No function matches the given name and argument types 'isfinite(INTERVAL)'` | | A string | Error: `Could not choose a best candidate function`; cast it to `DATE` or `TIMESTAMP` first | | A boolean, `BLOB` or list | Error: `No function matches the given name and argument types`, for example `'isfinite(BOOLEAN)'` | | A number, such as `isfinite(1.5)` | `true`: the [number form](/develop/docs/dev-database-reference-sql-functions-numeric-isfinite) | 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-date-time-isfinite#set-up-the-examples): ``` run(f"SELECT id, isfinite(d), isfinite(ts) FROM {TABLE} WHERE id = 4") run("SELECT isfinite(NULL), isfinite(DATE 'infinity'), isfinite(DATE '-infinity'), isfinite(TIMESTAMP 'infinity'), " "isfinite(TIMESTAMP '-infinity'), isfinite(CAST('infinity' AS TIMESTAMP_NS)), isfinite(TIMESTAMPTZ 'infinity')") run("SELECT isfinite(DATE '0001-01-01'), isfinite(DATE '9999-12-31'), isfinite(CAST('0044-03-15 (BC)' AS DATE)), " "isfinite(1.5)") run("SELECT isfinite(TIME '13:45:30')") run("SELECT isfinite(INTERVAL '1 day')") run("SELECT isfinite('2024-02-29')") run("SELECT isfinite(true)") ``` ``` [(4, None, None)] [(None, False, False, False, False, False, False)] [(True, True, True, True)] InternalError: Binder Error: No function matches the given name and argument types 'isfinite(TIME)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'isfinite(INTERVAL)'. You might need to add explicit type casts. InternalError: Binder Error: Could not choose a best candidate function for the function call "isfinite(STRING_LITERAL)". In order to select one, please add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'isfinite(BOOLEAN)'. You might need to add explicit type casts. ``` ## Examples Every event in the table has an ordinary date and timestamp, so `isfinite` is `true` for each, and `NULL` for row 4: ``` run(f"SELECT id, isfinite(d), isfinite(ts), isfinite(tns) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, True, True, True), (2, True, True, True), (3, True, True, True), (4, None, None, None), (5, True, True, True)] ``` Keep only the rows with an ordinary date. Row 4 is left out because `isfinite(NULL)` is `NULL`, not `true`: ``` run(f"SELECT id FROM {TABLE} WHERE isfinite(d) ORDER BY id LIMIT 10") ``` ``` [(1,), (2,), (3,), (5,)] ``` ## 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 `isfinite()` is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `isfinite()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `isfinite()` 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 isfinite(d)") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ isfinite(d) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ d │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Combine it with a pushed-down condition.** In `id > 2 AND isfinite(d)`, `id > 2` is still evaluated in VAST DataBase, so `isfinite()` runs only on the rows that pass it. In the plan, the `FILTER` step holds only `isfinite(d)`: ``` plan(f"SELECT id FROM {TABLE} WHERE id > 2 AND isfinite(d)") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #0 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ isfinite(d) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ id │ │ d │ │ │ └───────────────────────────┘ ``` - **Store a flag if you filter on it often.** Compute `isfinite(d)` when you write the rows and keep it in a `BOOLEAN` column: a comparison of that column is pushed down, `isfinite(d)` isn't. ## Limitations and errors - **Dates and timestamps only.** A `TIME` or an `INTERVAL` has no special values; `isfinite` fails with `No function matches the given name and argument types`. - **Not for strings.** A string fails with `Could not choose a best candidate function`. Cast it first: `isfinite(CAST('2024-02-29' AS DATE))`. - **One argument.** `isfinite(ts, ts)` fails with `No function matches the given name and argument types 'isfinite(TIMESTAMP, TIMESTAMP)'`. ``` run("SELECT isfinite(CAST('2024-02-29' AS DATE))") run(f"SELECT isfinite(ts, ts) FROM {TABLE} LIMIT 1") ``` ``` [(True,)] InternalError: Binder Error: No function matches the given name and argument types 'isfinite(TIMESTAMP, TIMESTAMP)'. You might need to add explicit type casts. ``` ## Similar functions | Function | Returns | `DATE 'infinity'` | `TIMESTAMP '-infinity'` | `DATE '2026-03-01'` | | --- | --- | --- | --- | --- | | `isfinite` | Whether the value is an ordinary date or time | `false` | `false` | `true` | | [isinf](/develop/docs/dev-database-reference-sql-functions-date-time-isinf) | Whether the value is a special value | `true` | `true` | `false` | ``` run("SELECT isfinite(DATE 'infinity'), isfinite(TIMESTAMP '-infinity'), isfinite(DATE '2026-03-01'), " "isinf(DATE 'infinity'), isinf(TIMESTAMP '-infinity'), isinf(DATE '2026-03-01')") ``` ``` [(False, False, True, True, True, False)] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [isinf](/develop/docs/dev-database-reference-sql-functions-date-time-isinf): the opposite test. - [isfinite for numbers](/develop/docs/dev-database-reference-sql-functions-numeric-isfinite): `FLOAT` and `DOUBLE` values. - [Date and time functions](/develop/docs/dev-database-reference-sql-functions-date-time): all the date and time 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.