---
title: "second"
slug: "dev-database-reference-sql-functions-date-time-second"
updated: 2026-10-30T18:19:01Z
published: 2026-10-30T18:19:01Z
canonical: "docs.vastdata.com/dev-database-reference-sql-functions-date-time-second"
---

> ## 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.

# second

*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) › Parts of a date or time.* Returns the whole second of a timestamp or time of day, from 0 to 59, or the whole seconds of an interval. The fraction of the second is dropped.

## Syntax

```
second(value)
```

| Argument | Type | Description |
| --- | --- | --- |
| `value` | `TIMESTAMP` (also `TIMESTAMP_NS`, `TIMESTAMP_MS`, `TIMESTAMP_S`), `TIME`, `DATE` or `INTERVAL` | The value to take the second of. |

**Returns:** `BIGINT`.

**Same as:** `date_part('second', value)` and `extract(second FROM value)`; see [date_part](/develop/docs/dev-database-reference-sql-functions-date-time-date-part).

## 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_second`. 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_second"'

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, "<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

`second` returns the whole second of a timestamp or time of day, and drops the fraction: `second(TIMESTAMP &apos;2024-02-29 13:45:30.123456&apos;)` is `30`, and `second(TIME &apos;00:00:59.999999&apos;)` is `59`. It works on every timestamp precision (`TIMESTAMP`, `TIMESTAMP_NS`, `TIMESTAMP_MS`, `TIMESTAMP_S`). A `DATE` has no time, so its second is always `0`.

To keep the fraction, use [millisecond](/develop/docs/dev-database-reference-sql-functions-date-time-millisecond) or [microsecond](/develop/docs/dev-database-reference-sql-functions-date-time-microsecond). They return the seconds part *including* the whole seconds, in smaller units:

| Function | Result for `TIMESTAMP &apos;2024-02-29 13:45:30.123456&apos;` |
| --- | --- |
| `second` | `30` |
| `millisecond` | `30123` |
| `microsecond` | `30123456` |

On an `INTERVAL`, `second` returns the whole seconds within the minute of its time part:

| Interval | `second` | Why |
| --- | --- | --- |
| `INTERVAL &apos;1 year 2 months 3 days 04:05:06.789&apos;` | `6` | The seconds of 04:05:06.789, without the fraction |
| `INTERVAL &apos;90 seconds&apos;` | `30` | 90 seconds is 1 minute and 30 seconds |
| `INTERVAL &apos;1.5 seconds&apos;` | `1` | The fraction is dropped |
| `INTERVAL &apos;-0.5 seconds&apos;` | `0` | Less than a whole second |
| `INTERVAL &apos;-1 year -2 months -3 days -04:05:06.789&apos;` | `-6` | A negative interval gives a negative second |

## NULLs and edge cases

| Input | Result |
| --- | --- |
| A NULL value (row 4) | `NULL` |
| `DATE &apos;infinity&apos;`, `TIMESTAMP &apos;-infinity&apos;` | `NULL` |
| A `DATE` | `0` |
| `TIME &apos;00:00:59.999999&apos;` | `59` |
| `TIMESTAMP &apos;1969-12-31 23:59:59.999999&apos;` | `59` |
| A time with a time zone: `TIMETZ &apos;13:45:30.123456+02:30&apos;` | `30` |
| An untyped `NULL`: `second(NULL)` | Error: `Could not choose a best candidate function for the function call &quot;second(&quot;NULL&quot;)&quot;` |
| A string | Error: `Could not choose a best candidate function`; cast it to `TIME` or `TIMESTAMP` first |
| A number, boolean, `BLOB` or list | Error: `No function matches the given name and argument types`, for example `&apos;second(INTEGER_LITERAL)&apos;` |

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-second#set-up-the-examples):

```
run(f"SELECT id, second(ts), second(t) FROM {TABLE} WHERE id = 4")
run("SELECT second(DATE 'infinity'), second(TIMESTAMP '-infinity'), second(DATE '2026-03-01'), "
    "second(TIME '00:00:59.999999'), second(TIMESTAMP '1969-12-31 23:59:59.999999'), "
    "second(TIMETZ '13:45:30.123456+02:30')")
run("SELECT second(INTERVAL '1 year 2 months 3 days 04:05:06.789'), second(INTERVAL '90 seconds'), "
    "second(INTERVAL '1.5 seconds'), second(INTERVAL '-0.5 seconds'), "
    "second(INTERVAL '-1 year -2 months -3 days -04:05:06.789')")
run("SELECT second(NULL)")
run("SELECT second('13:45:30')")
run("SELECT second(123)")
```

```
[(4, None, None)]
[(None, None, 0, 59, 59, 30)]
[(6, 30, 1, 0, -6)]
InternalError: Binder Error: Could not choose a best candidate function for the function call "second("NULL")". In order to select one, please add explicit type casts.
InternalError: Binder Error: Could not choose a best candidate function for the function call "second(STRING_LITERAL)". In order to select one, please add explicit type casts.
InternalError: Binder Error: No function matches the given name and argument types 'second(INTEGER_LITERAL)'. You might need to add explicit type casts.
```

## Examples

The second of each event's timestamp and time of day, and the same with the fraction, in milliseconds:

```
run(f"SELECT id, second(ts), millisecond(ts), second(t) FROM {TABLE} ORDER BY id LIMIT 10")
```

```
[(1, 0, 0, 0), (2, 45, 45123, 45), (3, 0, 0, 0), (4, None, None, None), (5, 59, 59999, 59)]
```

Keep only the events that happened exactly on a minute (second 0):

```
run(f"SELECT id FROM {TABLE} WHERE second(ts) = 0 ORDER BY id LIMIT 10")
```

```
[(1,), (3,)]
```

## 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 `second()` is always computed by the Query Engine:

- **In the `SELECT` list,** the scan reads the column and the Query Engine computes `second()` for each row it returns.
- **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `second()` 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 second(ts) = 0")
```

```
┌───────────────────────────┐
│         PROJECTION        │
│    ────────────────────   │
│             #1            │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│           FILTER          │
│    ────────────────────   │
│     ("second"(ts) = 0)    │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│                           │
│        Projections:       │
│             ts            │
│             id            │
│                           │
└───────────────────────────┘
```

## Make it faster

- **Combine it with a range on the raw column.** In `ts &gt;= TIMESTAMP &apos;2026-03-01 00:00:00&apos; AND ts &lt; TIMESTAMP &apos;2026-03-02 00:00:00&apos; AND second(ts) = 0`, the range is still evaluated in VAST DataBase, so `second()` runs only on the rows of that day. The plan's `FILTER` step holds only the `second()` condition:

```
plan(f"SELECT id FROM {TABLE} WHERE ts >= TIMESTAMP '2026-03-01 00:00:00' AND ts < TIMESTAMP '2026-03-02 00:00:00' "
     "AND second(ts) = 0")
```

```
┌───────────────────────────┐
│         PROJECTION        │
│    ────────────────────   │
│             #1            │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│           FILTER          │
│    ────────────────────   │
│     ("second"(ts) = 0)    │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│                           │
│        Projections:       │
│             ts            │
│             id            │
│                           │
└───────────────────────────┘
```

- **Store the second if you filter on it often.** Compute it when you write the rows and keep it in its own column: `event_second = 0` is pushed down, `second(ts) = 0` isn't.

## Limitations and errors

- **No time-zone support.** On a `TIMESTAMP WITH TIME ZONE` value, such as `now()`, `second` fails with an `Extension Autoloading Error`. Cast the value to `TIMESTAMP` first; see [time zones](/develop/docs/dev-database-reference-sql-functions-date-time-time-zones).
- **Whole seconds only.** `second` drops the fraction; it doesn't round. Use [millisecond](/develop/docs/dev-database-reference-sql-functions-date-time-millisecond), [microsecond](/develop/docs/dev-database-reference-sql-functions-date-time-microsecond) or [nanosecond](/develop/docs/dev-database-reference-sql-functions-date-time-nanosecond) for the fraction.
- **No leap seconds.** A time with second 60, such as `TIMESTAMP &apos;2016-12-31 23:59:60&apos;`, isn't a valid value and fails with `invalid timestamp field format`.
- **`TIMESTAMP_NS` just before 1970.** Row 5's `tns`, `1969-12-31 23:59:59.999999999`, gives `0`, not `59`. Store such values as `TIMESTAMP` if you need their second.

```
run(f"SELECT id, second(tns), second(ts) FROM {TABLE} ORDER BY id LIMIT 10")
run("SELECT TIMESTAMP '2016-12-31 23:59:60'")
```

```
[(1, 0, 0), (2, 45, 45), (3, 0, 0), (4, None, None), (5, 0, 59)]
OSError: invalid timestamp field format: "2016-12-31 23:59:60", expected format is (YYYY-MM-DD HH:MM:SS[.US][±HH:MM| ZONE])
```

## Similar functions

| Function | Returns | Result for `TIMESTAMP &apos;2024-02-29 13:45:30.123456&apos;` (`second` gives `30`) |
| --- | --- | --- |
| [millisecond](/develop/docs/dev-database-reference-sql-functions-date-time-millisecond) | The seconds part with its fraction, in milliseconds | `30123` |
| [microsecond](/develop/docs/dev-database-reference-sql-functions-date-time-microsecond) | The seconds part with its fraction, in microseconds | `30123456` |
| [minute](/develop/docs/dev-database-reference-sql-functions-date-time-minute) | The minute, 0 to 59 | `45` |
| [date_trunc](/develop/docs/dev-database-reference-sql-functions-date-time-date-trunc) with `&apos;second&apos;` | The value without its fraction, as a `TIMESTAMP` | `2024-02-29 13:45:30` |
| [strftime](/develop/docs/dev-database-reference-sql-functions-date-time-strftime) with `&apos;%S&apos;` | The second as two-digit text | `&apos;30&apos;` |

```
run("SELECT second(TIMESTAMP '2024-02-29 13:45:30.123456'), millisecond(TIMESTAMP '2024-02-29 13:45:30.123456'), "
    "microsecond(TIMESTAMP '2024-02-29 13:45:30.123456'), minute(TIMESTAMP '2024-02-29 13:45:30.123456'), "
    "date_trunc('second', TIMESTAMP '2024-02-29 13:45:30.123456'), strftime(TIMESTAMP '2024-02-29 13:45:30.123456', '%S')")
```

```
[(30, 30123, 30123456, 45, datetime.datetime(2024, 2, 29, 13, 45, 30), '30')]
```

Clean up:

```
run(f"DROP TABLE IF EXISTS {TABLE}")
run(f"DROP SCHEMA IF EXISTS {SCHEMA}")
conn.close()
```

```
[]
[]
```

## See also

- [date_part](/develop/docs/dev-database-reference-sql-functions-date-time-date-part): any part of a value, by name.
- [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.