---
title: InfluxQL subqueries
description: An InfluxQL subquery is a query nested in the FROM clause of an InfluxQL query. The outer query queries results returned by the inner query (subquery).
url: https://docs.influxdata.com/influxdb3/clustered/reference/influxql/subqueries/
estimated_tokens: 5442
product: InfluxDB Clustered
version: clustered
---

# InfluxQL subqueries

An InfluxQL subquery is a query nested in the `FROM` clause of an InfluxQL query. The outer query queries results returned by the inner query (subquery).

-   [Syntax](#syntax)
-   [Examples](#examples)
-   [Notable subquery behaviors](#notable-subquery-behaviors)

InfluxQL does not support a `HAVING` clause, however InfluxQL subqueries offer functionality similar to the [SQL `HAVING` clause](/influxdb3/clustered/reference/sql/having/).

## Syntax

```sql
SELECT_clause FROM ( SELECT_statement ) [...]
```

When using subqueries, InfluxQL **performs the inner query first**, then performs the outer query.

The outer query requires a [`SELECT` clause](/influxdb3/clustered/reference/influxql/select/#select-clause) and a [`FROM` clause](/influxdb3/clustered/reference/influxql/select/#from-clause). The inner query is enclosed in parentheses in the outer query’s `FROM` clause.

InfluxQL supports multiple nested subqueries:

```sql
SELECT_clause FROM ( SELECT_clause FROM ( SELECT_statement ) [...] ) [...]
```

## Examples

#### Sample data

The examples below use the following sample data sets:

-   [Get started home sensor data](/influxdb3/clustered/reference/sample-data/#home-sensor-data)
-   [Random numbers sample data](/influxdb3/clustered/reference/sample-data/#random-numbers-sample-data)

[](#apply-an-aggregate-function-to-an-aggregated-result-set)

Apply an aggregate function to an aggregated result set

```sql
SELECT
  SUM(max)
FROM
  (
    SELECT
      MAX(temp)
    FROM
      home
    GROUP BY
      room
  )
```

Table: home

| time | sum |
| --- | --- |
| 1970-01-01T00:00:00Z | 46.1 |

[](#calculate-the-average-difference-between-two-fields)

Calculate the average difference between two fields

```sql
SELECT
  MEAN(difference)
FROM
  (
    SELECT
      a - b AS difference
    FROM
      numbers
  )
```

Table: numbers

| time | mean |
| --- | --- |
| 1970-01-01T00:00:00Z | -0.03629771779732732 |

[](#filter-aggregate-values-based-on-a-threshold)

Filter aggregate values based on a threshold

```sql
SELECT
  co_change
FROM
  (
    SELECT
      SPREAD(co) AS co_change
    FROM
      home
    GROUP BY
      room,
      time(2h)
  )
WHERE
  time >= '2022-01-01T08:00:00Z'
  AND time <= '2022-01-01T20:00:00Z'
  AND co_change >= 4
```

Table: home

| time | co_chnage |
| --- | --- |
| 2022-01-01T18:00:00Z | 4 |
| 2022-01-01T18:00:00Z | 5 |

[](#perform-additional-aggregate-operations-on-aggregate-values)

Perform additional aggregate operations on aggregate values

```sql
SELECT
  SUM(co_derivative) AS sum_derivative
FROM
  (
    SELECT
      DERIVATIVE(MEAN(co)) AS co_derivative
    FROM
      home
    GROUP BY
      time(12m),
      room
  )
WHERE
  time >= '2022-01-01T08:00:00Z'
  AND time <= '2022-01-01T20:00:00Z'
GROUP BY
  room
```

Table: home

| time | room | sum_derivative |
| --- | --- | --- |
| 1970-01-01T00:00:00Z | Kitchen | 5.2 |
| 1970-01-01T00:00:00Z | Living Room | 3.4 |

## Notable subquery behaviors

-   [Apply time bounds to the outer query to improve performance](#apply-time-bounds-to-the-outer-query-to-improve-performance)
-   [Cannot use multiple SELECT statements in a subquery](#cannot-use-multiple-select-statements-in-a-subquery)

### Apply time bounds to the outer query to improve performance

To improve the performance of InfluxQL queries that use subqueries and a specified time range, apply the `WHERE` clause with time-based predicates to the outer query rather than the inner query. For example–the following queries return the same results, but **the query with time-based predicate on the outer query is more performant than the query with time-based predicate on the inner query**:

#### Time bounds on the outer query

```sql
SELECT
  inner_value AS value
FROM
  (
    SELECT
      raw_value as inner_value
  )
WHERE
  time >= '2022-01-01T08:00:00Z'
  AND time <= '2022-01-01T20:00:00Z'
```

#### Time bounds on the inner query

```sql
SELECT
  inner_value AS value
FROM
  (
    SELECT
      raw_value as inner_value
    WHERE
      time >= '2022-07-19T08:00:00Z'
      AND time <= '2022-01-01T20:00:00Z'
  )
```

### Cannot use multiple SELECT statements in a subquery

InfluxQL does not support multiple [`SELECT` statements](/influxdb3/clustered/reference/influxql/select/) per subquery:

```sql
SELECT_clause FROM (SELECT_statement; SELECT_statement) [...]
```

However, InfluxQL does support multiple nested subqueries per outer query:

```sql
SELECT_clause FROM ( SELECT_clause FROM ( SELECT_statement ) [...] ) [...]
                     ------------------   ----------------
                         Subquery 1          Subquery 2
```