add influxql integral function (#6236)

Co-authored-by: Jason Stirnaman <[email protected]>

Author: sanderson

content/shared/influxql-v3-reference/feature-support.md

@@ -65,41 +65,37 @@ The following table provides information about what metaqueries are available in
 
 ### Aggregate functions
 
-| Function                                                                                  |        Supported         |
-| :---------------------------------------------------------------------------------------- | :----------------------: |
+| Function                                                                          |        Supported         |
+| :-------------------------------------------------------------------------------- | :----------------------: |
 | [COUNT()](/influxdb/version/reference/influxql/functions/aggregates/#count)       | **{{< icon "check" >}}** |
 | [DISTINCT()](/influxdb/version/reference/influxql/functions/aggregates/#distinct) | **{{< icon "check" >}}** |
-| <span style="opacity: .5;">INTEGRAL()</span>                                              |                          |
+| [INTEGRAL()](/influxdb/version/reference/influxql/functions/aggregates/#integral) | **{{< icon "check" >}}** |
 | [MEAN()](/influxdb/version/reference/influxql/functions/aggregates/#mean)         | **{{< icon "check" >}}** |
 | [MEDIAN()](/influxdb/version/reference/influxql/functions/aggregates/#median)     | **{{< icon "check" >}}** |
 | [MODE()](/influxdb/version/reference/influxql/functions/aggregates/#mode)         | **{{< icon "check" >}}** |
 | [SPREAD()](/influxdb/version/reference/influxql/functions/aggregates/#spread)     | **{{< icon "check" >}}** |
 | [STDDEV()](/influxdb/version/reference/influxql/functions/aggregates/#stddev)     | **{{< icon "check" >}}** |
 | [SUM()](/influxdb/version/reference/influxql/functions/aggregates/#sum)           | **{{< icon "check" >}}** |
 
-<!--
-INTEGRAL [influxdb_iox#6937](https://github.com/influxdata/influxdb_iox/issues/6937)
--->
-
 ### Selector functions
 
-| Function                                                                                     |        Supported         |
-| :------------------------------------------------------------------------------------------- | :----------------------: |
+| Function                                                                             |        Supported         |
+| :----------------------------------------------------------------------------------- | :----------------------: |
 | [BOTTOM()](/influxdb/version/reference/influxql/functions/selectors/#bottom)         | **{{< icon "check" >}}** |
 | [FIRST()](/influxdb/version/reference/influxql/functions/selectors/#first)           | **{{< icon "check" >}}** |
 | [LAST()](/influxdb/version/reference/influxql/functions/selectors/#last)             | **{{< icon "check" >}}** |
 | [MAX()](/influxdb/version/reference/influxql/functions/selectors/#max)               | **{{< icon "check" >}}** |
 | [MIN()](/influxdb/version/reference/influxql/functions/selectors/#min)               | **{{< icon "check" >}}** |
 | [PERCENTILE()](/influxdb/version/reference/influxql/functions/selectors/#percentile) | **{{< icon "check" >}}** |
-| <span style="opacity: .5;">SAMPLE()</span>                                                   |                          |
+| <span style="opacity: .5;">SAMPLE()</span>                                           |                          |
 | [TOP()](/influxdb/version/reference/influxql/functions/selectors/#top)               | **{{< icon "check" >}}** |
 
 <!-- SAMPLE() [influxdb_iox#6935](https://github.com/influxdata/influxdb_iox/issues/6935) -->
 
 ### Transformations
 
-| Function                                                                                                                     |        Supported         |
-| :--------------------------------------------------------------------------------------------------------------------------- | :----------------------: |
+| Function                                                                                                             |        Supported         |
+| :------------------------------------------------------------------------------------------------------------------- | :----------------------: |
 | [ABS()](/influxdb/version/reference/influxql/functions/transformations/#abs)                                         | **{{< icon "check" >}}** |
 | [ACOS()](/influxdb/version/reference/influxql/functions/transformations/#acos)                                       | **{{< icon "check" >}}** |
 | [ASIN()](/influxdb/version/reference/influxql/functions/transformations/#asin)                                       | **{{< icon "check" >}}** |

content/shared/influxql-v3-reference/functions/aggregates.md

@@ -6,24 +6,14 @@ _Examples use the sample data set provided in the
 
 - [COUNT()](#count)
 - [DISTINCT()](#distinct)
+- [INTEGRAL()](#integral)
 - [MEAN()](#mean)
 - [MEDIAN()](#median)
 - [MODE()](#mode)
 - [SPREAD()](#spread)
 - [STDDEV()](#stddev)
 - [SUM()](#sum)
 
-<!-- When implemented, place back in alphabetical order -->
-<!-- - [INTEGRAL()](#integral) -->
-
-> [!Important]
-> #### Missing InfluxQL functions
-> 
-> Some InfluxQL functions are in the process of being rearchitected to work with
-> the InfluxDB 3 storage engine. If a function you need is not here, check the
-> [InfluxQL feature support page](/influxdb/version/reference/influxql/feature-support/#function-support)
-> for more information.
-
 ## COUNT()
 
 Returns the number of non-null [field values](/influxdb/version/reference/glossary/#field-value).
@@ -186,14 +176,14 @@ name: home
 {{% /expand %}}
 {{< /expand-wrapper >}}
 
-<!-- ## INTEGRAL()
+## INTEGRAL()
 
 Returns the area under the curve for queried [field values](/influxdb/version/reference/glossary/#field-value)
 and converts those results into the summed area per **unit** of time.
 
-> [!Note]
-> `INTEGRAL()` does not support [`fill()`](/influxdb/version/query-data/influxql/explore-data/group-by/> #group-by-time-intervals-and-fill).
-> `INTEGRAL()` supports int64 and float64 field value [data types](/influxdb/version/reference/glossary/#data-type).
+> [!Important]
+> - `INTEGRAL()` does not support [`fill()`](/influxdb/version/reference/influxql/group-by/#group-by-time-and-fill-gaps).
+> - `INTEGRAL()` supports int64 and float64 field value [data types](/influxdb/version/reference/glossary/#data-type).
 
 ```sql
 INTEGRAL(field_expression[, unit])
@@ -318,7 +308,7 @@ name: home
 {{% /influxdb/custom-timestamps %}}
 
 {{% /expand %}}
-{{< /expand-wrapper >}} -->
+{{< /expand-wrapper >}}
 
 ## MEAN()