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Add note about time-bound subquery performance (#2943) 

* Add note about time-bound subquery performance, closes influxdata/DAR#117

* fixed typos
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Scott Anderson 2021-08-02 10:41:48 -06:00 committed by GitHub
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content/enterprise_influxdb/v1.9/query_language/explore-data.md
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@ -3163,6 +3163,31 @@ Sample syntax for multiple subqueries:
SELECT_clause FROM ( SELECT_clause FROM ( SELECT_statement ) [...] ) [...]
```
{{% note %}}
#### Improve performance of time-bound subqueries
To improve the performance of InfluxQL queries with time-bound subqueries,
apply the `WHERE time` clause to the outer query instead of the inner query.
For example, the following queries return the same results, but **the query with
time bounds on the outer query is more performant than the query with time
bounds on the inner query**:
##### Time bounds on the outer query (recommended)
```sql
SELECT inner_value AS value FROM (SELECT raw_value as inner_value)
WHERE time >= '2020-07-19T21:00:00Z'
AND time <= '2020-07-20T22:00:00Z'
```
##### Time bounds on the inner query
```sql
SELECT inner_value AS value FROM (
SELECT raw_value as inner_value
WHERE time >= '2020-07-19T21:00:00Z'
AND time <= '2020-07-20T22:00:00Z'
)
```
{{% /note %}}
### Examples
#### Calculate the [`SUM()`](/enterprise_influxdb/v1.9/query_language/functions/#sum) of several [`MAX()`](/enterprise_influxdb/v1.9/query_language/functions/#max) values

25
content/influxdb/v1.7/query_language/data_exploration.md
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@ -3173,6 +3173,31 @@ Sample syntax for multiple subqueries:
SELECT_clause FROM ( SELECT_clause FROM ( SELECT_statement ) [...] ) [...]
```
{{% note %}}
#### Improve performance of time-bound subqueries
To improve the performance of InfluxQL queries with time-bound subqueries,
apply the `WHERE time` clause to the outer query instead of the inner query.
For example, the following queries return the same results, but **the query with
time bounds on the outer query is more performant than the query with time
bounds on the inner query**:
##### Time bounds on the outer query (recommended)
```sql
SELECT inner_value AS value FROM (SELECT raw_value as inner_value)
WHERE time >= '2020-07-19T21:00:00Z'
AND time <= '2020-07-20T22:00:00Z'
```
##### Time bounds on the inner query
```sql
SELECT inner_value AS value FROM (
SELECT raw_value as inner_value
WHERE time >= '2020-07-19T21:00:00Z'
AND time <= '2020-07-20T22:00:00Z'
)
```
{{% /note %}}
### Examples
#### Calculate the [`SUM()`](/influxdb/v1.7/query_language/functions/#sum) of several [`MAX()`](/influxdb/v1.7/query_language/functions/#max) values

25
content/influxdb/v1.8/query_language/explore-data.md
View File

@ -3168,6 +3168,31 @@ Sample syntax for multiple subqueries:
SELECT_clause FROM ( SELECT_clause FROM ( SELECT_statement ) [...] ) [...]
```
{{% note %}}
#### Improve performance of time-bound subqueries
To improve the performance of InfluxQL queries with time-bound subqueries,
apply the `WHERE time` clause to the outer query instead of the inner query.
For example, the following queries return the same results, but **the query with
time bounds on the outer query is more performant than the query with time
bounds on the inner query**:
##### Time bounds on the outer query (recommended)
```sql
SELECT inner_value AS value FROM (SELECT raw_value as inner_value)
WHERE time >= '2020-07-19T21:00:00Z'
AND time <= '2020-07-20T22:00:00Z'
```
##### Time bounds on the inner query
```sql
SELECT inner_value AS value FROM (
SELECT raw_value as inner_value
WHERE time >= '2020-07-19T21:00:00Z'
AND time <= '2020-07-20T22:00:00Z'
)
```
{{% /note %}}
### Examples
#### Calculate the [`SUM()`](/influxdb/v1.8/query_language/functions/#sum) of several [`MAX()`](/influxdb/v1.8/query_language/functions/#max) values