--- title: "/ (divide an interval)" slug: "dev-database-reference-sql-functions-date-time-divide" updated: 2026-10-30T18:19:01Z published: 2026-10-30T18:19:01Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-date-time-divide" --- > ## 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. # / (divide an interval) *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) › Adding and interval arithmetic.* Divides an interval by a whole number. The months, days and time of day are divided separately, and each drops its remainder. ## Syntax ``` interval / n ``` | Argument | Type | Description | | --- | --- | --- | | `interval` | `INTERVAL` | The interval to divide. | | `n` | A whole number (`INTEGER` or `BIGINT`) | The divisor. | **Returns:** `INTERVAL`. ## 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_divide`. 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. A table can't have an `INTERVAL` column, so the examples build intervals from two timestamps: `ended - started` is an interval of days and time. This block connects, defines the `run()` and `plan()` helpers, and creates a table of five trips, each split into a number of legs. Row 4 has no values, and row 5 has no legs: ``` 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_divide"' 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}.trips" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, started TIMESTAMP, ended TIMESTAMP, legs BIGINT)") run(f"INSERT INTO {TABLE} VALUES " "(1, TIMESTAMP '2026-03-01 08:00:00', TIMESTAMP '2026-03-02 09:00:00', 2), " "(2, TIMESTAMP '2026-03-01 08:00:00', TIMESTAMP '2026-03-03 08:00:00', 4), " "(3, TIMESTAMP '2026-03-01 08:00:00', TIMESTAMP '2026-03-01 08:00:01', 3), " "(4, NULL, NULL, NULL), " "(5, TIMESTAMP '2026-03-01 08:00:00', TIMESTAMP '2026-03-01 10:00:00', 0)") ``` ``` [] [] [(5,)] ``` ## What it does An interval has three fields: months, days, and a time (stored in nanoseconds). `/` divides each field by `n` on its own, as a whole-number division, and drops the remainder. Nothing carries over from one field to the next: - `INTERVAL 3 DAY / 2` is 1 day, and `INTERVAL 1 DAY / 2` is 0: half a day isn't carried into the time. - `INTERVAL 1 MONTH / 2` is 0: half a month isn't carried into the days. - `INTERVAL 25 HOUR / 2` is 12 hours 30 minutes: hours are part of the time field, which divides down to the microsecond. - `INTERVAL '1 month 1 day 01:00:00' / 2` is 30 minutes: the month and the day both divide to 0. To split a duration evenly whatever its fields, convert it to seconds first; see [Similar functions](/develop/docs/dev-database-reference-sql-functions-date-time-divide#similar-functions). ## NULLs and edge cases | Input | Result | | --- | --- | | `INTERVAL 1 DAY / NULL`, `NULL::INTERVAL / 2` | `NULL` | | `INTERVAL 1 DAY / 0` | `NULL` | | `INTERVAL 1 DAY / -1` | -1 day | | `INTERVAL 1 SECOND / 3` | 0.333333 seconds (the time field keeps microseconds) | | `INTERVAL 1 DAY / 2.0` | Error: `No function matches the given name and argument types '/(INTERVAL, DECIMAL(2,1))'` | | `INTERVAL 1 DAY / CAST(2 AS DOUBLE)` | Error: `No function matches the given name and argument types '/(INTERVAL, DOUBLE)'` | | `INTERVAL 1 DAY / INTERVAL 1 HOUR` | Error: `No function matches the given name and argument types '/(INTERVAL, INTERVAL)'` | | `2 / INTERVAL 1 DAY` | Error: `No function matches the given name and argument types '/(INTEGER_LITERAL, INTERVAL)'` | | `DATE '2026-01-01' / 2` | Error: `No function matches the given name and argument types '/(DATE, INTEGER_LITERAL)'` | The same cases, as the cluster returns them, with the examples from [What it does](/develop/docs/dev-database-reference-sql-functions-date-time-divide#what-it-does). They use the helpers from [Set up the examples](/develop/docs/dev-database-reference-sql-functions-date-time-divide#set-up-the-examples): ``` run("SELECT INTERVAL 3 DAY / 2, INTERVAL 1 DAY / 2, INTERVAL 1 MONTH / 2, INTERVAL 25 HOUR / 2, " "INTERVAL '1 month 1 day 01:00:00' / 2") run("SELECT INTERVAL 1 DAY / NULL, NULL::INTERVAL / 2, INTERVAL 1 DAY / 0, INTERVAL 1 DAY / -1, INTERVAL 1 SECOND / 3") run("SELECT INTERVAL 1 DAY / 2.0") run("SELECT INTERVAL 1 DAY / CAST(2 AS DOUBLE)") run("SELECT INTERVAL 1 DAY / INTERVAL 1 HOUR") run("SELECT 2 / INTERVAL 1 DAY") run("SELECT DATE '2026-01-01' / 2") ``` ``` [(MonthDayNano(months=0, days=1, nanoseconds=0), MonthDayNano(months=0, days=0, nanoseconds=0), MonthDayNano(months=0, days=0, nanoseconds=0), MonthDayNano(months=0, days=0, nanoseconds=45000000000000), MonthDayNano(months=0, days=0, nanoseconds=1800000000000))] [(None, None, None, MonthDayNano(months=0, days=-1, nanoseconds=0), MonthDayNano(months=0, days=0, nanoseconds=333333000))] InternalError: Binder Error: No function matches the given name and argument types '/(INTERVAL, DECIMAL(2,1))'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types '/(INTERVAL, DOUBLE)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types '/(INTERVAL, INTERVAL)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types '/(INTEGER_LITERAL, INTERVAL)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types '/(DATE, INTEGER_LITERAL)'. You might need to add explicit type casts. ``` ## Examples The length of each leg. `ended - started` is in days and time, so trip 1 (1 day 1 hour, 2 legs) gives 30 minutes, not 12 hours 30 minutes: the day divides to 0 and the hour to 30 minutes. Trip 2 (2 days, 4 legs) gives 0, and trip 5 (0 legs) gives `NULL`: ``` run(f"SELECT id, ended - started, (ended - started) / legs FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, MonthDayNano(months=0, days=1, nanoseconds=3600000000000), MonthDayNano(months=0, days=0, nanoseconds=1800000000000)), (2, MonthDayNano(months=0, days=2, nanoseconds=0), MonthDayNano(months=0, days=0, nanoseconds=0)), (3, MonthDayNano(months=0, days=0, nanoseconds=1000000000), MonthDayNano(months=0, days=0, nanoseconds=333333000)), (4, None, None), (5, MonthDayNano(months=0, days=0, nanoseconds=7200000000000), None)] ``` Keep the trips whose legs are longer than an hour: ``` run(f"SELECT id FROM {TABLE} WHERE (ended - started) / legs > INTERVAL 1 HOUR ORDER BY id LIMIT 10") ``` ``` [] ``` ## 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 expression of columns, so `/` on an interval is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the columns and the Query Engine computes the interval and divides it 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 expression 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 (ended - started) / legs > INTERVAL 1 HOUR") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #3 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (normalized_interval(( │ │ (ended - started) / legs))│ │ > '01:00:00'::INTERVAL) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ ended │ │ started │ │ legs │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Store the duration if you filter on it often.** Compute it when you write the rows, for example as whole seconds in a `BIGINT` column. A comparison of that column with a constant is pushed down to VAST DataBase, so rows that don't match never leave storage; `(ended - started) / legs > INTERVAL 1 HOUR` isn't. - **Combine it with a pushed-down condition.** In `started >= TIMESTAMP '2026-03-01 00:00:00' AND (ended - started) / legs > INTERVAL 1 HOUR`, the comparison of `started` with a constant is still evaluated in VAST DataBase, so the division runs only on the rows that pass it. ## Limitations and errors - **Whole-number divisors only.** A decimal or `DOUBLE` divisor fails with `No function matches the given name and argument types`, for example `'/(INTERVAL, DOUBLE)'`. To divide by a fraction, convert the interval to seconds with [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch), divide, and convert back with [to_seconds](/develop/docs/dev-database-reference-sql-functions-date-time-to-seconds). - **Each field drops its remainder.** See [What it does](/develop/docs/dev-database-reference-sql-functions-date-time-divide#what-it-does). It matters for any interval with days or months, including the difference of two timestamps, which is in days and time. Divide the [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) value instead. - **No interval by interval.** To get the ratio of two intervals, divide their [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) values. - **No function form, no `//`.** `divide(INTERVAL 1 DAY, 2)` fails with `No function matches the given name and argument types 'divide(INTERVAL, INTEGER_LITERAL)'`, and `INTERVAL 1 DAY // 2` with `'//(INTERVAL, INTEGER_LITERAL)'`. Use `/`. ``` run("SELECT divide(INTERVAL 1 DAY, 2)") run("SELECT INTERVAL 1 DAY // 2") ``` ``` InternalError: Binder Error: No function matches the given name and argument types 'divide(INTERVAL, INTEGER_LITERAL)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types '//(INTERVAL, INTEGER_LITERAL)'. You might need to add explicit type casts. ``` ## Similar functions | Function | Does | Result for `INTERVAL 1 DAY` and 2 (`/` gives 0) | | --- | --- | --- | | [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) then `/` | The interval in seconds, as a `DOUBLE`, divided: no remainder is dropped | `43200.0` | | [to_seconds](/develop/docs/dev-database-reference-sql-functions-date-time-to-seconds) of that | Back to an interval, in seconds | 12 hours | | [* (multiply)](/develop/docs/dev-database-reference-sql-functions-date-time-multiply) | Multiplies each field by a whole number | 2 days for `* 2` | | [normalized_interval](/develop/docs/dev-database-reference-sql-functions-date-time-normalized-interval) | Rewrites an interval's fields; it isn't a division | (not a division) | ``` run("SELECT INTERVAL 1 DAY / 2, epoch(INTERVAL 1 DAY) / 2, to_seconds(epoch(INTERVAL 1 DAY) / 2), INTERVAL 1 DAY * 2") run(f"SELECT id, to_seconds(epoch(ended - started) / legs) FROM {TABLE} WHERE legs > 0 ORDER BY id LIMIT 10") ``` ``` [(MonthDayNano(months=0, days=0, nanoseconds=0), 43200.0, MonthDayNano(months=0, days=0, nanoseconds=43200000000000), MonthDayNano(months=0, days=2, nanoseconds=0))] [(1, MonthDayNano(months=0, days=0, nanoseconds=45000000000000)), (2, MonthDayNano(months=0, days=0, nanoseconds=43200000000000)), (3, MonthDayNano(months=0, days=0, nanoseconds=333333000))] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [+ (plus)](/develop/docs/dev-database-reference-sql-functions-date-time-plus) and [- (minus)](/develop/docs/dev-database-reference-sql-functions-date-time-minus): add an interval to a date or timestamp, and the difference of two timestamps. - [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.