--- title: "to_centuries" slug: "dev-database-reference-sql-functions-date-time-to-centuries" updated: 2026-10-30T18:19:01Z published: 2026-10-30T18:19:01Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-date-time-to-centuries" --- > ## 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. # to_centuries *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) › Interval constructors.* Returns an `INTERVAL` of `n` centuries. Add it to a date or timestamp to move it by whole centuries. ## Syntax ``` to_centuries(n) ``` | Argument | Type | Description | | --- | --- | --- | | `n` | `INTEGER` (a `SMALLINT`, or a string such as `'2'`, is converted) | The number of centuries. Negative values give a negative interval. | **Returns:** `INTERVAL`, held as `n` × 1200 months. **Same as:** `to_years(n * 100)`; for one century, the literal `INTERVAL 1 CENTURY`. ## 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_to_centuries`. 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 spans. Each has a count `n` (an `INTEGER`) and a start time `ts`. Row 1 starts on 29 February, and row 4 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_date_time_to_centuries"' 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}.spans" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, n INTEGER, ts TIMESTAMP)") run(f"INSERT INTO {TABLE} VALUES " "(1, 1, TIMESTAMP '2024-02-29 00:00:00'), " "(2, -2, TIMESTAMP '2026-01-31 12:00:00'), " "(3, 0, TIMESTAMP '2026-03-01 08:30:45'), " "(4, NULL, NULL)") ``` ``` [] [] [(4,)] ``` ## What it does `to_centuries(n)` returns an interval of `n` centuries, held as `n` × 1200 months with no days and no time. The ADBC driver shows it as a `MonthDayNano` value: `to_centuries(2)` is `MonthDayNano(months=2400, days=0, nanoseconds=0)`. Adding the interval to a date or timestamp moves it by whole calendar months, so the time of day and, where the month allows, the day of the month are kept: `TIMESTAMP '2024-02-29 00:00:00' + to_centuries(1)` is `2124-02-29 00:00:00`. A `DATE` plus the interval is a `TIMESTAMP`: `DATE '2026-01-31' + to_centuries(1)` is `2126-01-31 00:00:00`. Because the interval is a number of months, its length in seconds depends on how you count a month. [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) counts a year as 365.25 days, and [epoch_us](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-us) counts a month as 30 days: | Expression | Result | | --- | --- | | `epoch(to_centuries(1))` | `3155760000.0` (seconds) | | `epoch_us(to_centuries(1))` | `3110400000000000` (microseconds) | ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL`, or a NULL value (row 4) | `NULL` | | `0` | An empty interval: `months=0` | | `-1` | `months=-1200` | | `1789569`, the largest that fits | `months=2147482800` | | `1789570` | Error: `Interval value 1789570 centuries out of range` | | `'2'` (a string) | `months=2400`: the same as the integer | | A `SMALLINT`: `CAST(2 AS SMALLINT)` | `months=2400` | | A `BIGINT`: `CAST(2 AS BIGINT)`, or a `BIGINT` column | Error: `No function matches the given name and argument types 'to_centuries(BIGINT)'` | | A fraction, such as `1.5` (a `DOUBLE` fails the same way, naming `DOUBLE`) | Error: `No function matches the given name and argument types 'to_centuries(DECIMAL(2,1))'` | | A `DATE`, an `INTERVAL` or a boolean | Error: `No function matches the given name and argument types`, for example `'to_centuries(BOOLEAN)'` | 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-to-centuries#set-up-the-examples): ``` run(f"SELECT id, to_centuries(n) FROM {TABLE} WHERE id = 4") run("SELECT to_centuries(NULL), to_centuries(0), to_centuries(-1), to_centuries(1789569), to_centuries('2'), to_centuries(CAST(2 AS SMALLINT))") run("SELECT to_centuries(1789570)") run("SELECT to_centuries(CAST(2 AS BIGINT))") run("SELECT to_centuries(1.5)") run("SELECT to_centuries(true)") ``` ``` [(4, None)] [(None, MonthDayNano(months=0, days=0, nanoseconds=0), MonthDayNano(months=-1200, days=0, nanoseconds=0), MonthDayNano(months=2147482800, days=0, nanoseconds=0), MonthDayNano(months=2400, days=0, nanoseconds=0), MonthDayNano(months=2400, days=0, nanoseconds=0))] OSError: Interval value 1789570 centuries out of range InternalError: Binder Error: No function matches the given name and argument types 'to_centuries(BIGINT)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'to_centuries(DECIMAL(2,1))'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'to_centuries(BOOLEAN)'. You might need to add explicit type casts. ``` ## Examples The interval for each row's count, and the start time moved by it: ``` run(f"SELECT id, n, to_centuries(n), ts + to_centuries(n) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 1, MonthDayNano(months=1200, days=0, nanoseconds=0), datetime.datetime(2124, 2, 29, 0, 0)), (2, -2, MonthDayNano(months=-2400, days=0, nanoseconds=0), datetime.datetime(1826, 1, 31, 12, 0)), (3, 0, MonthDayNano(months=0, days=0, nanoseconds=0), datetime.datetime(2026, 3, 1, 8, 30, 45)), (4, None, None, None)] ``` `id` is a `BIGINT`, which `to_centuries` doesn't take. Cast it to `INTEGER` first: ``` run(f"SELECT id, to_centuries(CAST(id AS INTEGER)) FROM {TABLE} ORDER BY id LIMIT 10") run(f"SELECT to_centuries(id) FROM {TABLE} LIMIT 1") ``` ``` [(1, MonthDayNano(months=1200, days=0, nanoseconds=0)), (2, MonthDayNano(months=2400, days=0, nanoseconds=0)), (3, MonthDayNano(months=3600, days=0, nanoseconds=0)), (4, MonthDayNano(months=4800, days=0, nanoseconds=0))] InternalError: Binder Error: No function matches the given name and argument types 'to_centuries(BIGINT)'. You might need to add explicit type casts. ``` ## 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 `to_centuries()` of a column is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `to_centuries()` 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 condition and keeps the rows that match. No rows are skipped in storage. The plan of a condition on `ts + to_centuries(n)` shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE ts + to_centuries(n) > TIMESTAMP '2030-01-01 00:00:00'") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #2 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ ((ts + to_centuries(n)) > │ │ '2030-01-01 00:00:00': │ │ :TIMESTAMP) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ ts │ │ n │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Put the interval on the constant side.** `ts > TIMESTAMP '2030-01-01 00:00:00' - to_centuries(1)` compares the raw column with a value the Query Engine computes once, so the comparison is 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 ts > TIMESTAMP '2030-01-01 00:00:00' - to_centuries(1)") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Store the end time if you filter on it often.** If each row's span is `n` centuries, compute `ts + to_centuries(n)` when you write the row and keep it in its own `TIMESTAMP` column: a comparison of that column with a constant is pushed down. ## Limitations and errors - **`INTEGER` only.** A `BIGINT` fails with `No function matches the given name and argument types 'to_centuries(BIGINT)'`; cast it with `CAST(x AS INTEGER)`. A fraction fails too: for part of a century, use [to_years](/develop/docs/dev-database-reference-sql-functions-date-time-to-years) or [to_months](/develop/docs/dev-database-reference-sql-functions-date-time-to-months) with a whole number of years or months. - **Range.** `n` can be at most 1789569 (and at least -1789569), because the interval's months must fit in an `INTEGER`. Beyond that it fails with `Interval value ... centuries out of range`. - **No time-zone support.** Adding an interval to a `TIMESTAMP WITH TIME ZONE`, such as `now()`, fails. Cast the value to `TIMESTAMP` first; see [time zones](/develop/docs/dev-database-reference-sql-functions-date-time-time-zones). ## Similar functions | Function | Returns | Example | | --- | --- | --- | | `INTERVAL 1 CENTURY` | The same interval, as a literal | `INTERVAL 1 CENTURY` = `to_centuries(1)` | | [to_years](/develop/docs/dev-database-reference-sql-functions-date-time-to-years) | An interval of `n` years | `to_years(100)` = `to_centuries(1)` | | [to_months](/develop/docs/dev-database-reference-sql-functions-date-time-to-months) | An interval of `n` months | `to_months(1200)` = `to_centuries(1)` | | [to_decades](/develop/docs/dev-database-reference-sql-functions-date-time-to-decades) | An interval of `n` decades (120 months each) | `to_decades(10)` = `to_centuries(1)` | | [to_millennia](/develop/docs/dev-database-reference-sql-functions-date-time-to-millennia) | An interval of `n` millennia (12,000 months each) | `to_millennia(1)` = `to_centuries(10)` | | [normalized_interval](/develop/docs/dev-database-reference-sql-functions-date-time-normalized-interval) | The interval with its fields carried over; months stay months | `normalized_interval(to_centuries(100))` is `months=120000` | ``` run("SELECT to_centuries(1) = INTERVAL 1 CENTURY, to_centuries(1) = to_years(100), to_centuries(1) = to_months(1200)") run("SELECT epoch(to_centuries(1)), epoch_us(to_centuries(1)), normalized_interval(to_centuries(100))") run("SELECT TIMESTAMP '2024-02-29 00:00:00' + to_centuries(1), DATE '2026-01-31' + to_centuries(1)") ``` ``` [(True, True, True)] [(3155760000.0, 3110400000000000, MonthDayNano(months=120000, days=0, nanoseconds=0))] [(datetime.datetime(2124, 2, 29, 0, 0), datetime.datetime(2126, 1, 31, 0, 0))] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [Date and time functions](/develop/docs/dev-database-reference-sql-functions-date-time): all the date and time functions, and the [interval constructors](/develop/docs/dev-database-reference-sql-functions-date-time#interval-constructors). - [plus](/develop/docs/dev-database-reference-sql-functions-date-time-plus): adding an interval to a date or timestamp. - [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.