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

> ## 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.

# dayofyear

*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) › Weeks and days of the week.* Returns the day of the year of a date or timestamp, from 1 for 1 January to 365, or 366 in a leap year.

## Syntax

```
dayofyear(value)
```

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

**Returns:** `BIGINT`.

**Same as:** `date_part('doy', value)`, also written `date_part('dayofyear', 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_dayofyear`. 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 seven 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, row 5 is a leap day, and row 6 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_dayofyear"'

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 '2024-02-29', TIMESTAMP '2024-02-29 00:00:00', TIME '00:00:00', "
    "CAST('2024-02-29 00:00:00' AS TIMESTAMP_NS)), "
    "(6, 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)), "
    "(7, DATE '2027-01-03', TIMESTAMP '2027-01-03 00:00:00.5', TIME '00:00:00.000001', "
    "CAST('2027-01-03 00:00:00.5' AS TIMESTAMP_NS))")
```

```
[]
[]
[(7,)]
```

## What it does

`dayofyear` counts the days from 1 January, which is day 1. After February, the same calendar date has a number one higher in a leap year:

| Date | Result |
| --- | --- |
| `DATE &apos;2026-03-01&apos;` | `60` |
| `DATE &apos;2024-03-01&apos;` (leap year) | `61` |
| `DATE &apos;2026-12-31&apos;` | `365` |
| `DATE &apos;2024-12-31&apos;` (leap year) | `366` |

## NULLs and edge cases

| Input | Result |
| --- | --- |
| A NULL value (row 4) | `NULL` |
| `DATE &apos;infinity&apos;`, `TIMESTAMP &apos;-infinity&apos;` | `NULL` |
| `DATE &apos;0001-01-01&apos;` | `1` |
| `DATE &apos;9999-12-31&apos;` | `365` |
| `TIMESTAMP &apos;1969-12-31 23:59:59.999999&apos;` | `365` |
| An untyped `NULL`: `dayofyear(NULL)` | Error: `Could not choose a best candidate function for the function call &quot;dayofyear(&quot;NULL&quot;)&quot;` |
| An `INTERVAL` | Error: `interval units &quot;doy&quot; not recognized` |
| A `TIME` | Error: `No function matches the given name and argument types &apos;dayofyear(TIME)&apos;` |
| A string | Error: `Could not choose a best candidate function`; cast it to `DATE` first |
| A number, boolean, `BLOB` or list | Error: `No function matches the given name and argument types`, for example `&apos;dayofyear(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-dayofyear#set-up-the-examples):

```
run(f"SELECT id, dayofyear(ts) FROM {TABLE} WHERE id = 4")
run("SELECT dayofyear(DATE '2026-03-01'), dayofyear(DATE '2024-03-01'), dayofyear(DATE '2026-12-31'), "
    "dayofyear(DATE '2024-12-31')")
run("SELECT dayofyear(DATE 'infinity'), dayofyear(TIMESTAMP '-infinity'), dayofyear(DATE '0001-01-01'), "
    "dayofyear(DATE '9999-12-31'), dayofyear(TIMESTAMP '1969-12-31 23:59:59.999999')")
run("SELECT dayofyear(NULL)")
run("SELECT dayofyear(INTERVAL '1 year 2 months 3 days')")
run("SELECT dayofyear(TIME '13:45:30')")
run("SELECT dayofyear('2026-03-01')")
run("SELECT dayofyear(123)")
```

```
[(4, None)]
[(60, 61, 365, 366)]
[(None, None, 1, 365, 365)]
InternalError: Binder Error: Could not choose a best candidate function for the function call "dayofyear("NULL")". In order to select one, please add explicit type casts.
OSError: interval units "doy" not recognized
InternalError: Binder Error: No function matches the given name and argument types 'dayofyear(TIME)'. You might need to add explicit type casts.
InternalError: Binder Error: Could not choose a best candidate function for the function call "dayofyear(STRING_LITERAL)". In order to select one, please add explicit type casts.
InternalError: Binder Error: No function matches the given name and argument types 'dayofyear(INTEGER_LITERAL)'. You might need to add explicit type casts.
```

## Examples

The day of the year of each event. Row 1 (28 February 2026) is day 59, and row 5 (29 February 2024) day 60:

```
run(f"SELECT id, d, dayofyear(d), dayofyear(ts) FROM {TABLE} ORDER BY id LIMIT 10")
```

```
[(1, datetime.date(2026, 2, 28), 59, 59), (2, datetime.date(2026, 3, 1), 60, 60), (3, datetime.date(2024, 12, 30), 365, 365), (4, None, None, None), (5, datetime.date(2024, 2, 29), 60, 60), (6, datetime.date(1969, 12, 31), 365, 365), (7, datetime.date(2027, 1, 3), 3, 3)]
```

Keep only the events in the first 60 days of their year, whatever the year:

```
run(f"SELECT id, d FROM {TABLE} WHERE dayofyear(d) <= 60 ORDER BY id LIMIT 10")
```

```
[(1, datetime.date(2026, 2, 28)), (2, datetime.date(2026, 3, 1)), (5, datetime.date(2024, 2, 29)), (7, datetime.date(2027, 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 `dayofyear()` is always computed by the Query Engine:

- **In the `SELECT` list,** the scan reads the column and the Query Engine computes `dayofyear()` for each row it returns.
- **In `WHERE`,** the scan sends the column for every row, and a `FILTER` step in the Query Engine computes `dayofyear()` 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, d FROM {TABLE} WHERE dayofyear(d) <= 60")
```

```
┌───────────────────────────┐
│         PROJECTION        │
│    ────────────────────   │
│             id            │
│             d             │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│           FILTER          │
│    ────────────────────   │
│    (dayofyear(d) <= 60)   │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│                           │
│        Projections:       │
│             d             │
│             id            │
│                           │
└───────────────────────────┘
```

## Make it faster

- **For days of one year, filter on a range of the raw column.** The first 60 days of 2026 are `d &gt;= DATE &apos;2026-01-01&apos; AND d &lt; DATE &apos;2026-03-02&apos;`. The range is pushed down to VAST DataBase, so rows outside it never leave storage. The plan for the range has no `FILTER` step:

```
plan(f"SELECT id, d FROM {TABLE} WHERE d >= DATE '2026-01-01' AND d < DATE '2026-03-02'")
```

```
┌───────────────────────────┐
│         PROJECTION        │
│    ────────────────────   │
│             id            │
│             d             │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│                           │
│        Projections:       │
│             d             │
│             id            │
│                           │
└───────────────────────────┘
```

- **Store the day of the year if you filter on it across years.** Compute it when you write the rows and keep it in its own column: `day_of_year &lt;= 60` is pushed down, `dayofyear(d) &lt;= 60` isn't.

## Limitations and errors

- **No time-zone support.** On a `TIMESTAMP WITH TIME ZONE` value, such as `now()`, `dayofyear` 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).
- **Not for `TIME` or `INTERVAL`.** The error for an `INTERVAL` lists `dayofyear(INTERVAL)` among the candidates, but running it fails with `interval units &quot;doy&quot; not recognized`.
- **`TIMESTAMP_NS` before 1970.** Row 6's `TIMESTAMP_NS` value `1969-12-31 23:59:59.999999999` gives `1`, while the `TIMESTAMP` value `1969-12-31 23:59:59.999999` gives `365`. If you need the day of nanosecond values before 1970 that are close to midnight, check the result or store the value as `TIMESTAMP`.
- **Other SQL dialects' names aren't available.** `day_of_year` and `doy` fail with `Scalar Function with name ... does not exist!`. Use `dayofyear`, or `date_part(&apos;doy&apos;, ...)`.

```
run(f"SELECT id, dayofyear(tns), dayofyear(ts) FROM {TABLE} WHERE id = 6")
run("SELECT day_of_year(DATE '2026-03-01')")
run("SELECT doy(DATE '2026-03-01')")
```

```
[(6, 1, 365)]
InternalError: Catalog Error: Scalar Function with name day_of_year does not exist!
InternalError: Catalog Error: Scalar Function with name doy does not exist!
```

## Similar functions

| Function | Returns | Result for `DATE &apos;2024-02-29&apos;` (`dayofyear` gives `60`) |
| --- | --- | --- |
| [day](/develop/docs/dev-database-reference-sql-functions-date-time-day) | The day of the month | `29` |
| [strftime](/develop/docs/dev-database-reference-sql-functions-date-time-strftime) with `&apos;%j&apos;` | The day of the year as text, padded to three digits | `&apos;060&apos;` |
| [date_part](/develop/docs/dev-database-reference-sql-functions-date-time-date-part) with `&apos;doy&apos;` | The same as `dayofyear` | `60` |

```
run("SELECT dayofyear(DATE '2024-02-29'), day(DATE '2024-02-29'), strftime(DATE '2024-02-29', '%j'), "
    "date_part('doy', DATE '2024-02-29')")
```

```
[(60, 29, '060', 60)]
```

Clean up:

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

```
[]
[]
```

## See also

- [day](/develop/docs/dev-database-reference-sql-functions-date-time-day): the day of the month.
- [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.