SQL aggregate functions (#4748)
* fix iox ui details (#4660) * fixed left nav for iox * updated nav order * one more nav fix * added sql data types doc to iox * removed, need to create separate branch * IOx get started (#4676) * WIP iox get started * WIP iox get started * WIP iox get started * WIP iox get-started * WIP get-started docs * iox get started setup * added custom times and datepicker to iox getting started * finished sample data date picker * WIP get started querying * wrapped up new getting started content * fixed unclosed shortcode * fixed js bug, updated get started to address PR feedback * removed influxdbu banner from iox-get-started * fixed typos * Migrate data to IOx (#4704) * WIP iox get started * WIP iox get started * WIP iox get started * WIP iox get-started * WIP get-started docs * iox get started setup * added custom times and datepicker to iox getting started * finished sample data date picker * WIP get started querying * wrapped up new getting started content * fixed unclosed shortcode * fixed js bug, updated get started to address PR feedback * removed influxdbu banner from iox-get-started * add tsm to iox migration guide * WIP 1.x iox migration * WIP iox migration guides * iox migration landing page content * updated migration docs to address PR feedback * one last PR feedback update * added sql reference for review * moved reference to sql folder * removed file * Schema recommendations for IOx (#4701) * WIP iox get started * WIP iox get started * WIP iox get started * WIP iox get-started * WIP get-started docs * iox get started setup * added custom times and datepicker to iox getting started * finished sample data date picker * WIP get started querying * wrapped up new getting started content * fixed unclosed shortcode * fixed js bug, updated get started to address PR feedback * removed influxdbu banner from iox-get-started * schema design recommendations * add heading color styles * fixed typos and formatting * fixed typos * fixed line protocol descrepencies * fixed typo * IOx landing page and notification (#4717) * updated cloud iox landing page * added state of the docs notification, removed addition resources from nav * updated iox page titles * updated duplicate oss and product data * add order by doc (#4710) * add order by doc * Update content/influxdb/cloud-iox/order-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/order-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/order-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/order-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/order-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/order-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update 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select doc (#4708) * added select doc * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/select.md Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> * having clause (#4713) * added having clause * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/having.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Apply suggestions from code review Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * added sql-data-types branch and corresponding doc (#4700) * added sql-data-types branch and corresponding doc * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update 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content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> * Update content/influxdb/cloud-iox/sql-data-types.md Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> * added interval * fixed formatting * more format fixes Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> * add limit doc (#4711) * add limit doc * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/limit.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * added group by (#4721) * added group by * Update content/influxdb/cloud-iox/group-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/group-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/group-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/group-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * Update content/influxdb/cloud-iox/group-by.md Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> --------- Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com> * IOx SQL query guides (#4720) * WIP basic sql query guide * WIP query guides * WIP query docs, updated query format * fleshed out sql aggregate query doc * updated aggregate query guide, added explore schema guide * fixed getting started link * IOx Grafana and Superset documentation (#4723) * iox grafana and superset documentation * updates to the superset and grafana docs * chore(grafana): Rework the documentation for a release instead of from source. (#4724) * chore(grafana): Rework the documentation for a release instead of from source. * chore: Typo. * chore: v0.1.0 will be the first release. * updates to address PR feedback * a few minor updates to the grafana doc * another minor update to grafana * fixed grafana archive name --------- Co-authored-by: Brett Buddin <brett@buddin.org> * rearranged docs * fix order by description * updated more sql reference doc descriptions * Add SQL selector functions (#4725) * WIP selector functions * WIP selector fns * wrapped up sql selector functions * relocated function docs * add iox regions doc * add messaging to guide users to the correct docs (#4728) * minor changes * added Flux reference * updated algolia tagging * add delete information to iox docs (#4727) * fixed typos * Add write content to the IOx docs (#4729) * ported telegraf write docs to iox * write content and updated reference * updated node deps * added link to selectors reference * WIP aggregate functions * WIP aggregate functions * added approx aggregate functions * added related links and page navs --------- Co-authored-by: lwandzura <51929958+lwandzura@users.noreply.github.com> Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org> Co-authored-by: Brett Buddin <brett@buddin.org>pull/4750/head
Scott Anderson
GitHub
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@ -11,6 +11,9 @@ menu:
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identifier: query-sql-aggregate
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weight: 203
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influxdb/cloud-iox/tags: [query, sql]
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related:
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- /influxdb/cloud-iox/reference/sql/functions/aggregate/
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- /influxdb/cloud-iox/reference/sql/functions/selector/
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list_code_example: |
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##### Aggregate fields by groups
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```sql
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@ -74,7 +77,7 @@ value of `room`.
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Use **aggregate functions** to aggregate values in a specified column for each
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group and return a single row per group containing the aggregate value.
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[View aggregate functions](#)
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[View aggregate functions](/influxdb/cloud-iox/reference/sql/functions/aggregate/)
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##### Basic aggregate query
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@ -87,7 +90,7 @@ SELECT AVG(co) from home
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Use **selector functions** to "select" a value from a specified column.
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The available selector functions are designed to work with time series data.
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[View selector functions](/influxdb/cloud-iox/reference/sql/functions/selectors/)
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[View selector functions](/influxdb/cloud-iox/reference/sql/functions/selector/)
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Each selector function returns a Rust _struct_ (similar to a JSON object)
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representing a single time and value from the specified column in the each group.
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@ -0,0 +1,726 @@
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---
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title: SQL aggregate functions
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list_title: Aggregate functions
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description: >
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Aggregate data with SQL aggregate functions.
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menu:
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influxdb_cloud_iox:
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name: Aggregate
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parent: sql-functions
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weight: 301
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related:
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- /influxdb/cloud-iox/query-data/sql/aggregate-select/
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---
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SQL aggregate functions aggregate values in a specified column for each
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group or SQL partition and return a single row per group containing the
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aggregate value.
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- [General aggregate functions](#general-aggregate-functions)
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- [avg](#avg)
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- [count](#count)
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- [max](#max)
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- [min](#min)
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- [sum](#sum)
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- [Statistical aggregate functions](#statistical-aggregate-functions)
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- [corr](#corr)
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- [covar](#covar)
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- [covar_pop](#covar_pop)
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- [covar_samp](#covar_samp)
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- [stddev](#stddev)
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- [stddev_pop](#stddev_pop)
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- [stddev_samp](#stddev_samp)
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- [var](#var)
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- [var_pop](#var_pop)
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- [var_samp](#var_samp)
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- [Approximate aggregate functions](#approximate-aggregate-functions)
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- [approx_distinct](#approx_distinct)
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- [approx_median](#approx_median)
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- [approx_percentile_cont](#approx_percentile_cont)
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- [approx_percentile_cont_with_weight](#approx_percentile_cont_with_weight)
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---
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## General aggregate functions
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- [avg](#avg)
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- [count](#count)
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- [max](#max)
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- [min](#min)
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- [sum](#sum)
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### avg
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Returns the average of numeric values in the specified column.
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```sql
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avg(expression)
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```
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##### Arguments:
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- **expression**: Column to operate on.
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##### Aliases:
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- `mean`
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{{< expand-wrapper >}}
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{{% expand "View `avg` query example" %}}
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```sql
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SELECT
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location,
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avg(water_level) AS water_level_avg
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FROM h2o_feet
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GROUP BY location
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```
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| location | water_level_avg |
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| :----------- | -----------------: |
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| coyote_creek | 5.359142420303919 |
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| santa_monica | 3.5307120942458843 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### count
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Returns the number of rows in the specified column.
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Count includes _null_ values in the total count.
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To exclude _null_ values from the total count, include `<column> IS NOT NULL`
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in the `WHERE` clause.
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```sql
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count(expression)
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```
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##### Arguments:
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- **expression**: Column to operate on.
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{{< expand-wrapper >}}
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{{% expand "View `count` query example" %}}
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```sql
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SELECT
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location,
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count(water_level) AS water_level_count
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FROM h2o_feet
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GROUP BY location
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```
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| location | water_level_count |
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| :----------- | ----------------: |
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| coyote_creek | 7604 |
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| santa_monica | 7654 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### max
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Returns the maximum value in the specified column.
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_To return both the maximum value and its associated timestamp, use
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[`selector_max`](/influxdb/cloud-iox/reference/sql/functions/selector/#selector_max)._
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##### Arguments:
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- **expression**: Column to operate on.
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{{< expand-wrapper >}}
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{{% expand "View `max` query example" %}}
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```sql
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SELECT
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location,
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max(water_level) AS water_level_max
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FROM h2o_feet
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GROUP BY location
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```
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| location | water_level_max |
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| :----------- | --------------: |
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| santa_monica | 7.205 |
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| coyote_creek | 9.964 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### min
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Returns the minimum value in the specified column.
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_To return both the minimum value and its associated timestamp, use
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[`selector_max`](/influxdb/cloud-iox/reference/sql/functions/selector/#selector_min)._
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##### Arguments:
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- **expression**: Column to operate on.
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{{< expand-wrapper >}}
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{{% expand "View `min` query example" %}}
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```sql
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SELECT
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location,
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min(water_level) AS water_level_min
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FROM h2o_feet
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GROUP BY location
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```
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| location | water_level_min |
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| :----------- | --------------: |
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| coyote_creek | -0.61 |
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| santa_monica | -0.243 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### sum
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Returns the sum of all values in the specified column.
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##### Arguments:
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- **expression**: Column to operate on.
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{{< expand-wrapper >}}
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{{% expand "View `sum` query example" %}}
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```sql
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SELECT
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location,
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sum(water_level) AS water_level_sum
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FROM h2o_feet
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GROUP BY location
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```
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| location | water_level_sum |
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| :----------- | -----------------: |
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| santa_monica | 27024.070369358 |
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| coyote_creek | 40750.918963991004 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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## Statistical aggregate functions
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- [corr](#corr)
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- [covar](#covar)
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- [covar_pop](#covar_pop)
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- [covar_samp](#covar_samp)
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- [stddev](#stddev)
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- [stddev_pop](#stddev_pop)
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- [stddev_samp](#stddev_samp)
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- [var](#var)
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- [var_pop](#var_pop)
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- [var_samp](#var_samp)
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### corr
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Returns the coefficient of correlation between two numeric values.
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```sql
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corr(expression1, expression2)
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```
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##### Arguments:
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- **expression1**: First column or literal value to operate on.
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- **expression2**: Second column or literal value to operate on.
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{{< expand-wrapper >}}
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{{% expand "View `corr` query example" %}}
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_The following example uses the sample data set provided in
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[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
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```sql
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SELECT
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room,
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corr(hum, temp) AS correlation
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FROM home
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GROUP BY room
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```
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| room | correlation |
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| :---------- | ------------------: |
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| Living Room | 0.43665270457835725 |
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| Kitchen | 0.6741766954929539 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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### covar
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Returns the covariance of a set of number pairs.
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```sql
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covar(expression1, expression2)
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```
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|
||||
##### Arguments:
|
||||
|
||||
- **expression1**: First column or literal value to operate on.
|
||||
- **expression2**: Second column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `covar` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
covar(hum, temp) AS covar
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression1**: First column or literal value to operate on.
|
||||
- **expression2**: Second column or literal value to operate on.
|
||||
|
||||
| room | covar |
|
||||
| :---------- | ------------------: |
|
||||
| Living Room | 0.03346153846153959 |
|
||||
| Kitchen | 0.11134615384615432 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### covar_pop
|
||||
|
||||
Returns the population covariance of a set of number pairs.
|
||||
|
||||
```sql
|
||||
covar_pop(expression1, expression2)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression1**: First column or literal value to operate on.
|
||||
- **expression2**: Second column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `covar_pop` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
covar_pop(hum, temp) AS covar_pop
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | covar_pop |
|
||||
| :---------- | -------------------: |
|
||||
| Kitchen | 0.10278106508875783 |
|
||||
| Living Room | 0.030887573964498087 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### covar_samp
|
||||
|
||||
Returns the sample covariance of a set of number pairs.
|
||||
|
||||
```sql
|
||||
covar_samp(expression1, expression2)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression1**: First column or literal value to operate on.
|
||||
- **expression2**: Second column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `covar_samp` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
covar_samp(hum, temp) AS covar_samp
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | covar_samp |
|
||||
| :---------- | ------------------: |
|
||||
| Kitchen | 0.11134615384615432 |
|
||||
| Living Room | 0.03346153846153959 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### stddev
|
||||
|
||||
Returns the standard deviation of a set of numbers.
|
||||
|
||||
```sql
|
||||
stddev(expression)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `stddev` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
stddev(co) AS stddev
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | stddev |
|
||||
| :---------- | ----------------: |
|
||||
| Living Room | 5.885662718931967 |
|
||||
| Kitchen | 9.321879418735037 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### stddev_pop
|
||||
|
||||
Returns the population standard deviation of a set of numbers.
|
||||
|
||||
```sql
|
||||
stddev_pop(expression)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `stddev_pop` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
stddev_pop(co) AS stddev_pop
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | stddev_pop |
|
||||
| :---------- | ----------------: |
|
||||
| Kitchen | 8.956172047894082 |
|
||||
| Living Room | 5.654761830612032 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### stddev_samp
|
||||
|
||||
Returns the sample standard deviation of a set of numbers.
|
||||
|
||||
```sql
|
||||
stddev_samp(expression)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `stddev_samp` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
stddev_samp(co) AS stddev_samp
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | stddev_samp |
|
||||
| :---------- | ----------------: |
|
||||
| Living Room | 5.885662718931967 |
|
||||
| Kitchen | 9.321879418735037 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
---
|
||||
|
||||
### var
|
||||
|
||||
Returns the statistical variance of a set of numbers.
|
||||
|
||||
```sql
|
||||
var(expression)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `var` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
var(co) AS var
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | var |
|
||||
| :---------- | ----------------: |
|
||||
| Living Room | 34.64102564102564 |
|
||||
| Kitchen | 86.89743589743587 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### var_pop
|
||||
|
||||
Returns the statistical population variance of a set of numbers.
|
||||
|
||||
```sql
|
||||
var_pop(expression)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `var_pop` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
var_pop(co) AS var_pop
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | var_pop |
|
||||
| :---------- | -----------------: |
|
||||
| Living Room | 31.976331360946745 |
|
||||
| Kitchen | 80.21301775147927 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### var_samp
|
||||
|
||||
Returns the statistical sample variance of a set of numbers.
|
||||
|
||||
```sql
|
||||
var_samp(expression)
|
||||
```
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `var_samp` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
var_samp(co) AS var_samp
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | var_samp |
|
||||
| :---------- | ----------------: |
|
||||
| Kitchen | 86.89743589743587 |
|
||||
| Living Room | 34.64102564102564 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
## Approximate aggregate functions
|
||||
|
||||
- [approx_distinct](#approx_distinct)
|
||||
- [approx_median](#approx_median)
|
||||
- [approx_percentile_cont](#approx_percentile_cont)
|
||||
- [approx_percentile_cont_with_weight](#approx_percentile_cont_with_weight)
|
||||
|
||||
### approx_distinct
|
||||
|
||||
Returns the approximate number of distinct input values calculated using the
|
||||
HyperLogLog algorithm.
|
||||
|
||||
```sql
|
||||
approx_distinct(expression)
|
||||
```
|
||||
|
||||
##### Arguments
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `approx_distinct` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
approx_distinct(co::string) AS approx_distinct
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | approx_distinct |
|
||||
| :---------- | --------------: |
|
||||
| Living Room | 7 |
|
||||
| Kitchen | 8 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### approx_median
|
||||
|
||||
Returns the approximate median (50th percentile) of input values.
|
||||
It is an alias of `approx_percentile_cont(x, 0.5)`.
|
||||
|
||||
```sql
|
||||
approx_median(expression)
|
||||
```
|
||||
|
||||
##### Arguments
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `approx_median` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
approx_median(temp) AS approx_median
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | approx_median |
|
||||
| :---------- | ------------: |
|
||||
| Kitchen | 22.7 |
|
||||
| Living Room | 22.3 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### approx_percentile_cont
|
||||
|
||||
Returns the approximate percentile of input values using the t-digest algorithm.
|
||||
|
||||
```sql
|
||||
approx_percentile_cont(expression, percentile, centroids)
|
||||
```
|
||||
|
||||
##### Arguments
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
- **percentile**: Percentile to compute. Must be a float value between 0 and 1 (inclusive).
|
||||
- **centroids**: Number of centroids to use in the t-digest algorithm. _Default is 100_.
|
||||
|
||||
If there are this number or fewer unique values, you can expect an exact result.
|
||||
A higher number of centroids results in a more accurate approximation, but
|
||||
requires more memory to compute.
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `approx_percentile_cont` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
approx_percentile_cont(temp, 0.99) AS "99th_percentile"
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | 99th_percentile |
|
||||
| :---------- | --------------: |
|
||||
| Kitchen | 23.3 |
|
||||
| Living Room | 22.8 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
||||
### approx_percentile_cont_with_weight
|
||||
|
||||
Returns the weighted approximate percentile of input values using the
|
||||
t-digest algorithm.
|
||||
|
||||
```sql
|
||||
approx_percentile_cont_with_weight(expression, weight, percentile)
|
||||
```
|
||||
|
||||
##### Arguments
|
||||
|
||||
- **expression**: Column or literal value to operate on.
|
||||
- **weight**: Column or literal value to use as weight.
|
||||
- **percentile**: Percentile to compute. Must be a float value between 0 and 1 (inclusive).
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
{{% expand "View `approx_percentile_cont_with_weight` query example" %}}
|
||||
|
||||
_The following example uses the sample data set provided in
|
||||
[Get started with InfluxDB tutorial](/influxdb/cloud-iox/get-started/write/#construct-line-protocol)._
|
||||
|
||||
```sql
|
||||
SELECT
|
||||
room,
|
||||
approx_percentile_cont_with_weight(temp, co, 0.99) AS "co_weighted_99th_percentile"
|
||||
FROM home
|
||||
GROUP BY room
|
||||
```
|
||||
|
||||
| room | co_weighted_99th_percentile |
|
||||
| :---------- | --------------------------: |
|
||||
| Kitchen | 23.3 |
|
||||
| Living Room | 22.8 |
|
||||
|
||||
{{% /expand %}}
|
||||
{{< /expand-wrapper >}}
|
||||
|
|
@ -5,9 +5,11 @@ description: >
|
|||
Select data with SQL selector functions.
|
||||
menu:
|
||||
influxdb_cloud_iox:
|
||||
name: Selectors
|
||||
name: Selector
|
||||
parent: sql-functions
|
||||
weight: 220
|
||||
weight: 302
|
||||
related:
|
||||
- /influxdb/cloud-iox/query-data/sql/aggregate-select/
|
||||
---
|
||||
|
||||
SQL selector functions are designed to work with time series data.
|
||||
|
|
@ -16,6 +18,13 @@ data and return a single value.
|
|||
However, selectors are unique in that they return a _struct_ that contains
|
||||
a **time value** in addition to the computed value.
|
||||
|
||||
- [How do selector functions work?](#how-do-selector-functions-work)
|
||||
- [Selector functions](#selector-functions)
|
||||
- [selector_min](#selector_min)
|
||||
- [selector_max](#selector_max)
|
||||
- [selector_first](#selector_first)
|
||||
- [selector_last](#selector_last)
|
||||
|
||||
## How do selector functions work?
|
||||
|
||||
Each selector function returns a Rust _struct_ (similar to a JSON object)
|
||||
|
|
@ -29,7 +38,7 @@ For example, `selector_first` returns the value of specified column in the first
|
|||
The struct returned from a selector function has two properties:
|
||||
|
||||
- **time**: `time` value in the selected row
|
||||
- **value**: value of the specified column in the selected row
|
||||
- **expression**: value of the specified column in the selected row
|
||||
|
||||
```js
|
||||
{time: 2023-01-01T00:00:00Z, value: 72.1}
|
||||
|
|
@ -59,15 +68,15 @@ GROUP BY room
|
|||
|
||||
### selector_min
|
||||
|
||||
`selector_min()` function returns the smallest value of a selected column and a timestamp.
|
||||
Returns the smallest value of a selected column and a timestamp.
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **value**: Column to operate on or a literal value.
|
||||
- **expression**: Column to operate on or a literal value.
|
||||
- **timestamp**: Time column or timestamp literal.
|
||||
|
||||
```sql
|
||||
selector_min(<value>, <timestamp>)
|
||||
selector_min(expression, timestamp)
|
||||
```
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
|
|
@ -89,15 +98,15 @@ FROM h2o_feet
|
|||
|
||||
### selector_max
|
||||
|
||||
`selector_max()` function returns the smallest value of a selected column and a timestamp.
|
||||
Returns the largest value of a selected column and a timestamp.
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **value**: Column to operate on or a literal value.
|
||||
- **expression**: Column to operate on or a literal value.
|
||||
- **timestamp**: Time column or timestamp literal.
|
||||
|
||||
```sql
|
||||
selector_max(<value>, <timestamp>)
|
||||
selector_max(expression, timestamp)
|
||||
```
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
|
|
@ -119,15 +128,15 @@ FROM h2o_feet
|
|||
|
||||
### selector_first
|
||||
|
||||
`selector_first()` returns the first value ordered by time ascending.
|
||||
Returns the first value ordered by time ascending.
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **value**: Column to operate on or a literal value.
|
||||
- **expression**: Column to operate on or a literal value.
|
||||
- **timestamp**: Time column or timestamp literal.
|
||||
|
||||
```sql
|
||||
selector_first(<value>, <timestamp>)
|
||||
selector_first(expression, timestamp)
|
||||
```
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
|
|
@ -149,15 +158,15 @@ FROM h2o_feet
|
|||
|
||||
### selector_last
|
||||
|
||||
`selector_last()` returns the last value ordered by time ascending.
|
||||
Returns the last value ordered by time ascending.
|
||||
|
||||
##### Arguments:
|
||||
|
||||
- **value**: Column to operate on or a value literal.
|
||||
- **expression**: Column to operate on or a value literal.
|
||||
- **timestamp**: Time column or timestamp literal.
|
||||
|
||||
```sql
|
||||
selector_last(<value>, <timestamp>)
|
||||
selector_last(expression, timestamp)
|
||||
```
|
||||
|
||||
{{< expand-wrapper >}}
|
||||
|
|
@ -4,4 +4,4 @@
|
|||
{{- $keepClass := cond ( $keep ) " keep" "" -}}
|
||||
{{- $isCloud := in $currentVersion "cloud" -}}
|
||||
{{- $versionText := cond ($isCloud) "Cloud" $currentVersion -}}
|
||||
<span class="current-version{{ $keepClass }}">{{- $versionText -}}</span>
|
||||
<span class="current-version{{ $keepClass }}">{{- $versionText -}}</span>
|
||||
|
|
|
|||
|
|
@ -8,7 +8,7 @@
|
|||
"autoprefixer": ">=10.2.5",
|
||||
"hugo-extended": ">=0.101.0",
|
||||
"postcss": ">=8.2.13",
|
||||
"postcss-cli": "=>9.1.0"
|
||||
"postcss-cli": ">=9.1.0"
|
||||
},
|
||||
"dependencies": {
|
||||
"axios": "^0.27.2",
|
||||
|
|
|
|||
Loading…
Reference in New Issue