--- title: "epoch_ms" slug: "dev-database-reference-sql-functions-date-time-epoch-ms" updated: 2026-10-30T18:19:01Z published: 2026-10-30T18:19:01Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-date-time-epoch-ms" --- > ## 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. # epoch_ms *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) › Epoch values.* Returns the number of whole milliseconds since 1970-01-01 00:00:00 of a date or timestamp, as a `BIGINT`. It also works the other way: given a `BIGINT` count of milliseconds, it returns the `TIMESTAMP`. ## Syntax ``` epoch_ms(value) epoch_ms(milliseconds) ``` | Argument | Type | Description | | --- | --- | --- | | `value` | `DATE`, `TIMESTAMP` (also `TIMESTAMP_NS`, `TIMESTAMP_MS`, `TIMESTAMP_S`), `TIMESTAMP WITH TIME ZONE`, `TIME`, `TIME WITH TIME ZONE` or `INTERVAL` | The value to convert to milliseconds. | | `milliseconds` | `BIGINT` (or a smaller integer type) | Milliseconds since 1970-01-01 00:00:00, to turn into a timestamp. | **Returns:** `BIGINT`; `TIMESTAMP` for `epoch_ms(milliseconds)`. ## 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_epoch_ms`. 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`), a timestamp with nanoseconds (`tns`) and a Unix time in milliseconds (`ms`). 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_epoch_ms"' 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, ms BIGINT)") 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), 1772320500000), " "(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), 1772353845123), " "(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), 0), " "(4, NULL, 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), -1)") ``` ``` [] [] [(5,)] ``` ## What it does `epoch_ms` has two forms: - **From a date or time value to milliseconds.** On a `TIMESTAMP` or `DATE`, the milliseconds since 1970-01-01 00:00:00; on a `TIME`, the milliseconds since midnight; on an `INTERVAL`, its length in milliseconds. The digits finer than a millisecond are dropped: `epoch_ms(TIMESTAMP '2024-02-29 13:45:30.123456')` is `1709214330123`. - **From milliseconds to a timestamp.** On a `BIGINT`, the `TIMESTAMP` that many milliseconds after 1970-01-01 00:00:00: `epoch_ms(1772353845123)` is `2026-03-01 08:30:45.123`, and `epoch_ms(-1)` is `1969-12-31 23:59:59.999`. Use it to read Unix times in milliseconds, as many systems write them. On a `TIMESTAMP WITH TIME ZONE`, the milliseconds count from 1970-01-01 00:00:00 UTC, so the offset is applied: `epoch_ms(TIMESTAMPTZ '2024-02-29 13:45:30.123456+02')` is `1709207130123`. On a `TIME WITH TIME ZONE`, the offset isn't applied: `epoch_ms(TIMETZ '13:45:30.123456+02:30')` is `49530123`. On an `INTERVAL`, `epoch_ms` counts a month as 30 days and a year as 12 months: `epoch_ms(INTERVAL '1 year')` is `31104000000` (360 days). [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) counts a year as 365.25 days instead. ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL`, or a NULL value (row 4) | `NULL` | | `DATE 'infinity'`, `TIMESTAMP '-infinity'` | `NULL` | | One microsecond before 1970 (row 5's `ts`) | `0`: the fraction isn't rounded down to `-1` | | `TIMESTAMP '1969-12-31 23:59:59.9995'` | `0` | | `DATE '0001-01-01'` | `-62135596800000` | | `INTERVAL '1 month'` | `2592000000` | | `INTERVAL '1 year 2 months 3 days 04:05:06.789'` | `36561906789` | | `epoch_ms(0)` | `1970-01-01 00:00:00` | | `epoch_ms(9223372036854)` | `2262-04-11 23:47:16.854` | | `epoch_ms(9223372036854775807)` | Error: `Could not convert Timestamp(MS) to Timestamp(US` | | A `DOUBLE` or `DECIMAL`, such as `epoch_ms(1.5e12)` | Error: `No function matches the given name and argument types 'epoch_ms(DOUBLE)'`; cast it to `BIGINT` first | | A string | Error: `Could not choose a best candidate function` | | A boolean, `BLOB` or list | Error: `No function matches the given name and argument types`, for example `'epoch_ms(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-epoch-ms#set-up-the-examples): ``` run(f"SELECT id, epoch_ms(ts), epoch_ms(ms) FROM {TABLE} WHERE id = 4") run("SELECT epoch_ms(NULL), epoch_ms(DATE 'infinity'), epoch_ms(TIMESTAMP '-infinity'), " "epoch_ms(TIMESTAMP '1969-12-31 23:59:59.999999'), epoch_ms(TIMESTAMP '1969-12-31 23:59:59.9995')") run("SELECT epoch_ms(DATE '0001-01-01'), epoch_ms(INTERVAL '1 month'), epoch_ms(INTERVAL '1 year 2 months 3 days 04:05:06.789')") run("SELECT epoch_ms(0), CAST(epoch_ms(9223372036854) AS VARCHAR)") run("SELECT epoch_ms(9223372036854775807)") run("SELECT epoch_ms(1.5e12)") run("SELECT epoch_ms('1772320500000')") run("SELECT epoch_ms(true)") ``` ``` [(4, None, None)] [(None, None, None, 0, 0)] [(-62135596800000, 2592000000, 36561906789)] [(datetime.datetime(1970, 1, 1, 0, 0), '2262-04-11 23:47:16.854')] OSError: Could not convert Timestamp(MS) to Timestamp(US) InternalError: Binder Error: No function matches the given name and argument types 'epoch_ms(DOUBLE)'. You might need to add explicit type casts. InternalError: Binder Error: Could not choose a best candidate function for the function call "epoch_ms(STRING_LITERAL)". In order to select one, please add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'epoch_ms(BOOLEAN)'. You might need to add explicit type casts. ``` ## Examples The milliseconds since 1970 of each event's date and timestamp, and the milliseconds since midnight of its time: ``` run(f"SELECT id, epoch_ms(d), epoch_ms(ts), epoch_ms(t) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 1772236800000, 1772320500000, 83700000), (2, 1772323200000, 1772353845123, 30645123), (3, 1735516800000, 1735560000000, 43200000), (4, None, None, None), (5, -86400000, 0, 86399999)] ``` Turn the Unix times in milliseconds into timestamps: ``` run(f"SELECT id, ms, epoch_ms(ms) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 1772320500000, datetime.datetime(2026, 2, 28, 23, 15)), (2, 1772353845123, datetime.datetime(2026, 3, 1, 8, 30, 45, 123000)), (3, 0, datetime.datetime(1970, 1, 1, 0, 0)), (4, None, None), (5, -1, datetime.datetime(1969, 12, 31, 23, 59, 59, 999000))] ``` Keep only the events after a Unix time in milliseconds. This works, but [Make it faster](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-ms#make-it-faster) has a faster way to write it: ``` run(f"SELECT id FROM {TABLE} WHERE epoch_ms(ts) > 1772300000000 ORDER BY id LIMIT 10") ``` ``` [(1,), (2,)] ``` ## 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 `epoch_ms()` of a column is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `epoch_ms()` for each row it returns. - **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `epoch_ms()` and keeps the rows that match. No rows are skipped in storage. This is the same for both forms. The plan of the `WHERE` example shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE epoch_ms(ts) > 1772300000000") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #1 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ (epoch_ms(ts) > │ │ 1772300000000) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ ts │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Apply `epoch_ms` to the constant, not to the column.** `ts > epoch_ms(1772300000000)` returns the same rows as `epoch_ms(ts) > 1772300000000`. The Query Engine computes the constant once, so the comparison of the raw column is pushed down to VAST DataBase, and the plan has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE ts > epoch_ms(1772300000000)") run(f"SELECT id FROM {TABLE} WHERE ts > epoch_ms(1772300000000) ORDER BY id LIMIT 10") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ [(1,), (2,)] ``` - **Store Unix times as `TIMESTAMP`.** If you load milliseconds, convert them once with `epoch_ms(ms)` when you write the rows. A `TIMESTAMP` column can be filtered with pushed-down comparisons and read with every date and time function. ## Limitations and errors - **Milliseconds only.** The reverse form loses the microseconds: `epoch_ms(epoch_ms(TIMESTAMP '2026-03-01 08:30:45.123456'))` is `2026-03-01 08:30:45.123`. For microseconds, use [epoch_us](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-us) and [make_timestamp](/develop/docs/dev-database-reference-sql-functions-date-time-make-timestamp). - **Only `epoch_ms` has the reverse form.** `epoch_us(1772353845123456)`, `epoch_ns(...)` and `epoch(...)` of a number fail with `No function matches the given name and argument types`. Use [make_timestamp](/develop/docs/dev-database-reference-sql-functions-date-time-make-timestamp) for microseconds, [make_timestamp_ns](/develop/docs/dev-database-reference-sql-functions-date-time-make-timestamp-ns) for nanoseconds and [to_timestamp](/develop/docs/dev-database-reference-sql-functions-date-time-to-timestamp) for seconds. - **Whole milliseconds as `BIGINT`.** A `DOUBLE` or `DECIMAL` count fails; cast it to `BIGINT` first. - **One argument.** `epoch_ms(ts, ts)` fails with `No function matches the given name and argument types 'epoch_ms(TIMESTAMP, TIMESTAMP)'`. ``` run("SELECT epoch_ms(epoch_ms(TIMESTAMP '2026-03-01 08:30:45.123456'))") run("SELECT epoch_us(1772353845123456)") run("SELECT epoch_ms(CAST(1.5e12 AS BIGINT))") run(f"SELECT epoch_ms(ts, ts) FROM {TABLE} LIMIT 1") ``` ``` [(datetime.datetime(2026, 3, 1, 8, 30, 45, 123000),)] InternalError: Binder Error: No function matches the given name and argument types 'epoch_us(INTEGER_LITERAL)'. You might need to add explicit type casts. [(datetime.datetime(2017, 7, 14, 2, 40),)] InternalError: Binder Error: No function matches the given name and argument types 'epoch_ms(TIMESTAMP, TIMESTAMP)'. You might need to add explicit type casts. ``` ## Similar functions | Function | Returns | Result for `TIMESTAMP '2024-12-30 13:45:30.123456'` (`epoch_ms` gives `1735566330123`) | | --- | --- | --- | | [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) | Seconds, as a `DOUBLE` with the fraction | `1735566330.123456` | | [epoch_us](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-us) | Whole microseconds | `1735566330123456` | | [epoch_ns](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-ns) | Whole nanoseconds | `1735566330123456000` | | [make_timestamp](/develop/docs/dev-database-reference-sql-functions-date-time-make-timestamp) with one argument | From microseconds to a `TIMESTAMP`: the reverse of `epoch_us` | `make_timestamp(1735566330123456)` gives `2024-12-30 13:45:30.123456` | | [to_timestamp](/develop/docs/dev-database-reference-sql-functions-date-time-to-timestamp) | From seconds to a `TIMESTAMP WITH TIME ZONE`: the reverse of `epoch` | (cast it to `TIMESTAMP`) | ``` run("SELECT epoch_ms(TIMESTAMP '2024-12-30 13:45:30.123456'), epoch(TIMESTAMP '2024-12-30 13:45:30.123456'), " "epoch_us(TIMESTAMP '2024-12-30 13:45:30.123456'), epoch_ns(TIMESTAMP '2024-12-30 13:45:30.123456')") run("SELECT epoch_ms(1735566330123), make_timestamp(1735566330123456), CAST(to_timestamp(1735566330.123456) AS TIMESTAMP)") ``` ``` [(1735566330123, 1735566330.123456, 1735566330123456, 1735566330123456000)] [(datetime.datetime(2024, 12, 30, 13, 45, 30, 123000), datetime.datetime(2024, 12, 30, 13, 45, 30, 123456), datetime.datetime(2024, 12, 30, 13, 45, 30, 123456))] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch), [epoch_us](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-us) and [epoch_ns](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-ns): seconds, microseconds and nanoseconds. - [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.