---
title: SQL conditional functions
description: Use conditional functions to conditionally handle null values in SQL queries.
url: https://docs.influxdata.com/influxdb3/enterprise/reference/sql/functions/conditional/
estimated_tokens: 1652
product: InfluxDB 3 Enterprise
version: enterprise
publisher: InfluxData
canonical: https://docs.influxdata.com/influxdb3/enterprise/reference/sql/functions/conditional/
date: '2025-09-05T08:26:38-06:00'
lastmod: '2025-09-05T08:26:38-06:00'
---

The InfluxDB 3 Enterprise SQL implementation supports the following conditional
functions for conditionally handling *null* values:

* [coalesce](#coalesce)
* [greatest](#greatest)
* [ifnull](#ifnull)
* [least](#least)
* [nullif](#nullif)
* [nvl](#nvl)
* [nvl2](#nvl2)

## coalesce

Returns the first of its arguments that is not *null*.
Returns *null* if all arguments are *null*.
This function is often used to substitute a default value for *null* values.

```sql
coalesce(expression1[, ..., expression_n])
```

##### Arguments

* **expression1, expression\_n**:
  Expression to use if previous expressions are *null*.
  Can be a constant, column, or function, and any combination of arithmetic operators.
  Pass as many expression arguments as necessary.

[](#view-coalesce-query-example)

View `coalesce` query example

```sql
SELECT
  val1,
  val2,
  val3,
  coalesce(val1, val2, val3, 'quz') AS coalesce
FROM
  (values ('foo', 'bar', 'baz'),
          (NULL, 'bar', 'baz'),
          (NULL, NULL, 'baz'),
          (NULL, NULL, NULL)
  ) data(val1, val2, val3)
```

|val1|val2|val3|coalesce|
|----|----|----|--------|
|foo |bar |baz |  foo   |
|    |bar |baz |  bar   |
|    |    |baz |  baz   |
|    |    |    |  quz   |

## greatest

Returns the greatest value in a list of expressions.
Returns *null* if all expressions are *null*.

```sql
greatest(expression1[, ..., expression_n])
```

##### Arguments

* **expression1, expression\_n**: Expressions to compare and return the greatest value.
  Can be a constant, column, or function, and any combination of arithmetic operators.
  Pass as many expression arguments as necessary.

[](#view-greatest-query-example)

View `greatest` query example

*The following example uses the[Random numbers sample dataset](/influxdb3/enterprise/reference/sample-data/#random-numbers-sample-data).*

```sql
SELECT time, greatest(a, b) AS greatest FROM numbers LIMIT 4
```

|       time        |     greatest      |
|-------------------|-------------------|
|2023-01-01T01:20:00|\-0.515490223280789|
|2023-01-01T01:21:00| 0.803201312042983 |
|2023-01-01T01:22:00| 0.970938142399892 |
|2023-01-01T01:23:00|0.0493748366311344 |

## ifnull

*Alias of [nvl](#nvl).*

## least

Returns the least value in a list of expressions.
Returns *null* if all expressions are *null*.

```sql
least(expression1[, ..., expression_n])
```

##### Arguments

* **expression1, expression\_n**: Expressions to compare and return the least value.
  Can be a constant, column, or function, and any combination of arithmetic operators.
  Pass as many expression arguments as necessary.

[](#view-least-query-example)

View `least` query example

*The following example uses the[Random numbers sample dataset](/influxdb3/enterprise/reference/sample-data/#random-numbers-sample-data).*

```sql
SELECT time, least(a, b) AS least FROM numbers LIMIT 4
```

|       time        |       least       |
|-------------------|-------------------|
|2023-01-01T00:10:00|\-1.08759833527982 |
|2023-01-01T00:11:00|\-0.187620086586211|
|2023-01-01T00:12:00|\-0.81371037157091 |
|2023-01-01T00:13:00|\-0.339781659874945|

## nullif

Returns *null* if *expression1* equals *expression2*; otherwise it returns *expression1*.
This can be used to perform the inverse operation of [`coalesce`](#coalesce).

```sql
nullif(expression1, expression2)
```

##### Arguments

* **expression1**: Expression to compare and return if equal to expression2.
  Can be a constant, column, or function, and any combination of arithmetic operators.
* **expression2**: Expression to compare to expression1.
  Can be a constant, column, or function, and any combination of arithmetic operators.

[](#view-nullif-query-example)

View `nullif` query example

```sql
SELECT
  value,
  nullif(value, 'baz') AS nullif
FROM
  (values ('foo'),
          ('bar'),
          ('baz')
  ) data(value)
```

|value|nullif|
|-----|------|
| foo | foo  |
| bar | bar  |
| baz |      |

## nvl

Returns *expression2* if *expression1* is *null*; otherwise it returns *expression1*.

```sql
nvl(expression1, expression2)
```

##### Arguments

* **expression1**: Return this expression if not *null*.
  Can be a constant, column, or function, and any combination of arithmetic operators.
* **expression2**: Return this expression if *expression1* is *null*.
  Can be a constant, column, or function, and any combination of arithmetic operators.

[](#view-nvl-query-example)

View `nvl` query example

```sql
SELECT
  value,
  nvl(value, 'baz') AS nvl
FROM
  (values ('foo'),
          ('bar'),
          (NULL)
  ) data(value)
```

|value|nvl|
|-----|---|
| foo |foo|
| bar |bar|
|     |baz|

## nvl2

Returns *expression2* if *expression1* is **not** *null*; otherwise it returns *expression3*.

```sql
nvl2(expression1, expression2, expression3)
```

##### Arguments

* **expression1**: First expression to test for *null*.
  Can be a constant, column, or function, and any combination of operators.
* **expression2**: Second expression to return if *expression1* is not *null*.
  Can be a constant, column, or function, and any combination of operators.
* **expression3**: Expression to return if *expression1* is *null*.
  Can be a constant, column, or function, and any combination of operators.

[](#view-nvl2-query-example)

View `nvl2` query example

```sql
SELECT
  val1,
  val2,
  val3,
  nvl2(val1, val2, val3) AS nvl2
FROM
  (values ('foo', 'bar', 'baz'),
          (NULL, 'bar', 'baz'),
          (NULL, NULL, 'baz'),
  ) data(val1, val2, val3)
```

|val1|val2|val3|nvl2|
|----|----|----|----|
|foo |bar |baz |bar |
|    |bar |baz |baz |
|    |    |baz |baz |
| val1 | val2 | val3 | coalesce |
| --- | --- | --- | --- |
| val1 | val2 | val3 | coalesce |
| foo | bar | baz | foo |
|  | bar | baz | bar |
|  |  | baz | baz |
|  |  |  | quz |

| time | greatest |
| --- | --- |
| time | greatest |
| 2023-01-01T01:20:00 | -0.515490223280789 |
| 2023-01-01T01:21:00 | 0.803201312042983 |
| 2023-01-01T01:22:00 | 0.970938142399892 |
| 2023-01-01T01:23:00 | 0.0493748366311344 |

| time | least |
| --- | --- |
| time | least |
| 2023-01-01T00:10:00 | -1.08759833527982 |
| 2023-01-01T00:11:00 | -0.187620086586211 |
| 2023-01-01T00:12:00 | -0.81371037157091 |
| 2023-01-01T00:13:00 | -0.339781659874945 |

| value | nullif |
| --- | --- |
| value | nullif |
| foo | foo |
| bar | bar |
| baz |  |

| value | nvl |
| --- | --- |
| value | nvl |
| foo | foo |
| bar | bar |
|  | baz |

| val1 | val2 | val3 | nvl2 |
| --- | --- | --- | --- |
| val1 | val2 | val3 | nvl2 |
| foo | bar | baz | bar |
|  | bar | baz | baz |
|  |  | baz | baz |