---
title: InfluxQL miscellaneous functions
description: Use InfluxQL miscellaneous functions to perform different operations in InfluxQL queries.
url: https://docs.influxdata.com/influxdb3/cloud-dedicated/reference/influxql/functions/misc/
estimated_tokens: 3828
product: InfluxDB Cloud Dedicated
version: cloud-dedicated
---

# InfluxQL miscellaneous functions

Use InfluxQL miscellaneous functions to perform different operations in InfluxQL queries.

-   [fill()](#fill)

## fill()

Fills *null* field values returned from empty time windows in `GROUP BY time()` queries with a specified fill value.

*Supported only in the [`GROUP BY` clause](/influxdb3/cloud-dedicated/reference/influxql/group-by/).*

```sql
fill(behavior)
```

#### Arguments

-   **behavior**: Defines the behavior of the fill operation. If no `FILL` clause is included, the default behavior is `fill(null)`.
    
    The following options are available:
    
    -   **numeric literal**: Replaces null values with the specified numeric literal.
    -   **linear**: Uses linear interpolation between existing values to replace null values.
    -   **none**: Removes rows with null field values.
    -   **null**: Keeps null values and associated timestamps.
    -   **previous**: Replaces null values with the most recent non-null value.

#### Examples

The following example uses the [Bitcoin price sample dataset](/influxdb3/cloud-dedicated/reference/sample-data/#bitcoin-price-data).

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**fill(numeric_literal):**

```sql
SELECT
  MEAN(price)
FROM bitcoin
WHERE
  code = 'USD'
  AND time >= '2023-05-01T00:00:00Z'
  AND time < '2023-05-01T02:00:00Z'
GROUP BY
  time(30m)
  fill(0)
```

name: bitcoin

| time | mean |
| --- | --- |
| 2023-05-01T00:00:00Z | 29319.9092 |
| 2023-05-01T00:30:00Z | 29307.4416 |
| 2023-05-01T01:00:00Z | 0 |
| 2023-05-01T01:30:00Z | 29263.2886 |

**fill(linear):**

```sql
SELECT
  MEAN(price)
FROM bitcoin
WHERE
  code = 'USD'
  AND time >= '2023-05-01T00:00:00Z'
  AND time < '2023-05-01T02:00:00Z'
GROUP BY
  time(30m)
  fill(linear)
```

name: bitcoin

| time | mean |
| --- | --- |
| 2023-05-01T00:00:00Z | 29319.9092 |
| 2023-05-01T00:30:00Z | 29307.4416 |
| 2023-05-01T01:00:00Z | 29285.3651 |
| 2023-05-01T01:30:00Z | 29263.2886 |

**fill(none):**

```sql
SELECT
  MEAN(price)
FROM bitcoin
WHERE
  code = 'USD'
  AND time >= '2023-05-01T00:00:00Z'
  AND time < '2023-05-01T02:00:00Z'
GROUP BY
  time(30m)
  fill(none)
```

name: bitcoin

| time | mean |
| --- | --- |
| 2023-05-01T00:00:00Z | 29319.9092 |
| 2023-05-01T00:30:00Z | 29307.4416 |
| 2023-05-01T01:30:00Z | 29263.2886 |

**fill(null):**

```sql
SELECT
  MEAN(price)
FROM bitcoin
WHERE
  code = 'USD'
  AND time >= '2023-05-01T00:00:00Z'
  AND time < '2023-05-01T02:00:00Z'
GROUP BY
  time(30m)
  fill(null)
```

name: bitcoin

| time | mean |
| --- | --- |
| 2023-05-01T00:00:00Z | 29319.9092 |
| 2023-05-01T00:30:00Z | 29307.4416 |
| 2023-05-01T01:00:00Z |  |
| 2023-05-01T01:30:00Z | 29263.2886 |

**fill(previous):**

```sql
SELECT
  MEAN(price)
FROM bitcoin
WHERE
  code = 'USD'
  AND time >= '2023-05-01T00:00:00Z'
  AND time < '2023-05-01T02:00:00Z'
GROUP BY
  time(30m)
  fill(previous)
```

name: bitcoin

| time | mean |
| --- | --- |
| 2023-05-01T00:00:00Z | 29319.9092 |
| 2023-05-01T00:30:00Z | 29307.4416 |
| 2023-05-01T01:00:00Z | 29307.4416 |
| 2023-05-01T01:30:00Z | 29263.2886 |

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