InfluxQL transformation functions

InfluxQL transformation functions modify and return values each row of queried data.

Each transformation function below covers syntax, including parameters to pass to the function, and examples of how to use the function. Examples use NOAA water sample data and data from sample_test.txt.

• ABS()
• ACOS()
• ASIN()
• ATAN()
• ATAN2()
• CEIL()
• COS()
• CUMULATIVE_SUM()
• DERIVATIVE()
• DIFFERENCE()
• ELAPSED()
• EXP()
• FLOOR()
• HISTOGRAM()
• LN()
• LOG()
• LOG2()
• LOG10()
• MOVING_AVERAGE()
• NON_NEGATIVE_DERIVATIVE()
• NON_NEGATIVE_DIFFERENCE
• POW
• ROUND
• SIN
• SQRT
• TAN

ABS()

Returns the absolute value of the field value. Supports GROUP BY clauses that group by tags but not group by time.

Basic syntax

SELECT ABS( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

ABS(field_key)
Returns the absolute values of field values associated with the field key.

ABS(*)
Returns the absolute values of field values associated with each field key in the measurement.

ABS() supports int64 and float64 field value data types.

Examples

SELECT ABS("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:15:00Z'

SELECT ABS(*) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:15:00Z'

SELECT ABS("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT ABS(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the ABS() function to those results.

ABS() supports the following nested functions:

COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT ABS(MEAN("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' GROUP BY time(12m)

ACOS()

Returns the arccosine (in radians) of the field value. Field values must be between -1 and 1. Supports GROUP BY clauses that group by tags but does not support group by time.

Basic syntax

SELECT ACOS( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

ACOS(field_key)
Returns the arccosine of field values associated with the field key.

ACOS(*)
Returns the arccosine of field values associated with each field key in the measurement.

ACOS() supports int64 and float64 field value data types with values between -1 and 1.

Examples

The examples below use a subset of data from sample_test.txt, which only includes field values within the calculable range (-1 to 1). This value range is required for the ACOS() function:

SELECT ACOS("a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ACOS(*) FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ACOS("a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT ACOS(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the ACOS() function to those results.

ACOS() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT ACOS(MEAN("a")) FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' GROUP BY time(3h)

ASIN()

Returns the arcsine (in radians) of the field value. Field values must be between -1 and 1.

Basic syntax

SELECT ASIN( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

ASIN(field_key)
Returns the arcsine of field values associated with the field key.

ASIN(*)
Returns the arcsine of field values associated with each field key in the measurement.

ASIN() supports int64 and float64 field value data types with values between -1 and 1.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use ASIN() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following data from sample_test.txt.

The following data from this data set only includes field value within the calculable range (-1 to 1) required for the ASIN() function:

SELECT ASIN("a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ASIN(*) FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ASIN("a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT ASIN(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the ASIN() function to those results.

ASIN() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT ASIN(MEAN("a")) FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' GROUP BY time(3h)

ATAN()

Returns the arctangent (in radians) of the field value. Field values must be between -1 and 1.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use ATAN() with a GROUP BY time() clause, see the Advanced syntax.

Basic syntax

SELECT ATAN( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

ATAN(field_key)
Returns the arctangent of field values associated with the field key.

ATAN(*)
Returns the arctangent of field values associated with each field key in the measurement.

ATAN() supports int64 and float64 field value data types with values between -1 and 1.

Examples

The examples below use a subset of data from sample_test.txt that only includes field values within the calculable range (-1 to 1) required for the of the ATAN() function.

SELECT ATAN("a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ATAN(*) FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ATAN("a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT ATAN(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the ATAN() function to those results.

ATAN() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples of advanced syntax

SELECT ATAN(MEAN("a")) FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' GROUP BY time(3h)

ATAN2()

Returns the the arctangent of y/x in radians.

Basic syntax

SELECT ATAN2( [ * | <field_key> | num ], [ <field_key> | num ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

ATAN2(field_key_y, field_key_x)
Returns the arctangent of field values associated with the field key, field_key_y, divided by field values associated with field_key_x.

ATAN2(*, field_key_x)
Returns the field values associated with each field key in the measurement divided by field values associated with field_key_x.

ATAN2() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use ATAN2() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use sample_test.txt.

SELECT ATAN2("a", "b") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ATAN2(*, "a") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z'

SELECT ATAN2("a", "b") FROM "data" WHERE time >= '2018-06-24T00:00:00Z' AND time <= '2018-06-25T00:00:00Z' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT ATAN2(<function()>, <function()>) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the ATAN2() function to those results.

ATAN2() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT ATAN2(MEAN("b"), MEAN("a")) FROM "data" WHERE time >= '2018-06-24T12:00:00Z' AND time <= '2018-06-25T00:00:00Z' GROUP BY time(2h)

CEIL()

Returns the subsequent value rounded up to the nearest integer.

Basic syntax

SELECT CEIL( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

CEIL(field_key)
Returns the field values associated with the field key rounded up to the nearest integer.

CEIL(*)
Returns the field values associated with each field key in the measurement rounded up to the nearest integer.

CEIL() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use CEIL() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

SELECT CEIL("water_level") FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

SELECT CEIL(*) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' 

SELECT CEIL("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT CEIL(<function>( [ * | <field_key> | /<regular_expression>/ ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the CEIL() function to those results.

CEIL() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT CEIL(MEAN("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(12m)

COS()

Returns the cosine of the field value.

Basic syntax

SELECT COS( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

COS(field_key)
Returns the cosine of field values associated with the field key.

COS(*)
Returns the cosine of field values associated with each field key in the measurement.

COS() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use COS() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT COS("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT COS(*) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT COS("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT COS(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the COS() function to those results.

COS() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT COS(MEAN("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(12m)

CUMULATIVE_SUM()

Returns the running total of subsequent field values.

Basic syntax

SELECT CUMULATIVE_SUM( [ * | <field_key> | /<regular_expression>/ ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

CUMULATIVE_SUM(field_key)
Returns the running total of subsequent field values associated with the field key.

CUMULATIVE_SUM(/regular_expression/)
Returns the running total of subsequent field values associated with each field key that matches the regular expression.

CUMULATIVE_SUM(*)
Returns the running total of subsequent field values associated with each field key in the measurement.

CUMULATIVE_SUM() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use CUMULATIVE_SUM() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT CUMULATIVE_SUM("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT CUMULATIVE_SUM(*) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT CUMULATIVE_SUM(/water/) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT CUMULATIVE_SUM("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT CUMULATIVE_SUM(<function>( [ * | <field_key> | /<regular_expression>/ ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the CUMULATIVE_SUM() function to those results.

CUMULATIVE_SUM() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT CUMULATIVE_SUM(MEAN("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(12m)

DERIVATIVE()

Returns the rate of change between subsequent field values.

Basic syntax

SELECT DERIVATIVE( [ * | <field_key> | /<regular_expression>/ ] [ , <unit> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

InfluxDB calculates the difference between subsequent field values and converts those results into the rate of change per unit. The unit argument is an integer followed by a duration and it is optional. If the query does not specify the unit the unit defaults to one second (1s).

DERIVATIVE(field_key)
Returns the rate of change between subsequent field values associated with the field key.

DERIVATIVE(/regular_expression/)
Returns the rate of change between subsequent field values associated with each field key that matches the regular expression.

DERIVATIVE(*)
Returns the rate of change between subsequent field values associated with each field key in the measurement.

DERIVATIVE() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use DERIVATIVE() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples in this section use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

SELECT DERIVATIVE("water_level") FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

(2.379 - 2.352) / (360s / 1s)

SELECT DERIVATIVE("water_level",6m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

(2.379 - 2.352) / (6m / 6m)

SELECT DERIVATIVE(*,3m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

(2.379 - 2.352) / (6m / 3m)

SELECT DERIVATIVE(/water/,2m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z'

(2.379 - 2.352)  / (6m / 2m)

SELECT DERIVATIVE("water_level") FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' ORDER BY time DESC LIMIT 1 OFFSET 2

(2.379 - 2.352) / (360s / 1s)

Advanced syntax

SELECT DERIVATIVE(<function> ([ * | <field_key> | /<regular_expression>/ ]) [ , <unit> ] ) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the DERIVATIVE() function to those results.

The unit argument is an integer followed by a duration and it is optional. If the query does not specify the unit the unit defaults to the GROUP BY time() interval. Note that this behavior is different from the basic syntax’s default behavior.

DERIVATIVE() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT DERIVATIVE(MEAN("water_level")) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' GROUP BY time(12m)

SELECT DERIVATIVE(MEAN("water_level"),6m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' GROUP BY time(12m)

DIFFERENCE()

Returns the result of subtraction between subsequent field values.

Syntax

SELECT DIFFERENCE( [ * | <field_key> | /<regular_expression>/ ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

DIFFERENCE(field_key)
Returns the difference between subsequent field values associated with the field key.

DIFFERENCE(/regular_expression/)
Returns the difference between subsequent field values associated with each field key that matches the regular expression.

DIFFERENCE(*)
Returns the difference between subsequent field values associated with each field key in the measurement.

DIFFERENCE() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use DIFFERENCE() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT DIFFERENCE("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT DIFFERENCE(*) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT DIFFERENCE(/water/) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT DIFFERENCE("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' ORDER BY time DESC LIMIT 2 OFFSET 2

Advanced syntax

SELECT DIFFERENCE(<function>( [ * | <field_key> | /<regular_expression>/ ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the DIFFERENCE() function to those results.

DIFFERENCE() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT DIFFERENCE(MAX("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(12m)

ELAPSED()

Returns the difference between subsequent field value’s timestamps.

Syntax

SELECT ELAPSED( [ * | <field_key> | /<regular_expression>/ ] [ , <unit> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

InfluxDB calculates the difference between subsequent timestamps. The unit option is an integer followed by a duration and it determines the unit of the returned difference. If the query does not specify the unit option the query returns the difference between timestamps in nanoseconds.

ELAPSED(field_key)
Returns the difference between subsequent timestamps associated with the field key.

ELAPSED(/regular_expression/)
Returns the difference between subsequent timestamps associated with each field key that matches the regular expression.

ELAPSED(*)
Returns the difference between subsequent timestamps associated with each field key in the measurement.

ELAPSED() supports all field value data types.

Examples

The examples use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z'

SELECT ELAPSED("water_level") FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z'

SELECT ELAPSED("water_level",1m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z'

SELECT ELAPSED(*,1m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z'

SELECT ELAPSED(/level/,1s) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z'

SELECT ELAPSED("water_level",1ms) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z' ORDER BY time DESC LIMIT 1 OFFSET 1

Common issues with ELAPSED()

ELAPSED() and units greater than the elapsed time

InfluxDB returns 0 if the unit option is greater than the difference between the timestamps.

Example

The timestamps in the h2o_feet measurement occur at six-minute intervals. If the query sets the unit option to one hour, InfluxDB returns 0:

SELECT ELAPSED("water_level",1h) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:12:00Z'

ELAPSED() with GROUP BY time() clauses

The ELAPSED() function supports the GROUP BY time() clause but the query results aren’t particularly useful. Currently, an ELAPSED() query with a nested function and a GROUP BY time() clause simply returns the interval specified in the GROUP BY time() clause.

The GROUP BY time() clause determines the timestamps in the results; each timestamp marks the start of a time interval. That behavior also applies to nested selector functions (like FIRST() or MAX()) which would, in all other cases, return a specific timestamp from the raw data. Because the GROUP BY time() clause overrides the original timestamps, the ELAPSED() calculation always returns the same value as the GROUP BY time() interval.

Example

In the codeblock below, the first query attempts to use the ELAPSED() function with a GROUP BY time() clause to find the time elapsed (in minutes) between minimum water_levels. Returns 12 minutes for both time intervals.

To get those results, InfluxDB first calculates the minimum water_levels at 12-minute intervals. The second query in the codeblock shows the results of that step. The step is the same as using the MIN() function with the GROUP BY time() clause and without the ELAPSED() function. Notice that the timestamps returned by the second query are 12 minutes apart. In the raw data, the first result (2.0930000000) occurs at 2019-08-18T00:42:00Z but the GROUP BY time() clause overrides that original timestamp. Because the timestamps are determined by the GROUP BY time() interval and not by the original data, the ELAPSED() calculation always returns the same value as the GROUP BY time() interval.

SELECT ELAPSED(MIN("water_level"),1m) FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:36:00Z' AND time <= '2019-08-18T00:54:00Z' GROUP BY time(12m)

SELECT MIN("water_level") FROM "h2o_feet" WHERE "location" = 'santa_monica' AND time >= '2019-08-18T00:36:00Z' AND time <= '2019-08-18T00:54:00Z' GROUP BY time(12m)

EXP()

Returns the exponential of the field value.

Syntax

SELECT EXP( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

EXP(field_key)
Returns the exponential of field values associated with the field key.

EXP(*)
Returns the exponential of field values associated with each field key in the measurement.

EXP() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use EXP() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT EXP("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT EXP(*) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT EXP("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT EXP(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the EXP() function to those results.

EXP() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT EXP(MEAN("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(12m)

FLOOR()

Returns the subsequent value rounded down to the nearest integer.

Syntax

SELECT FLOOR( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

FLOOR(field_key)
Returns the field values associated with the field key rounded down to the nearest integer.

FLOOR(*)
Returns the field values associated with each field key in the measurement rounded down to the nearest integer.

FLOOR() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use FLOOR() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT FLOOR("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT FLOOR(*) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT FLOOR("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' ORDER BY time DESC LIMIT 4 OFFSET 2

Advanced syntax

SELECT FLOOR(<function>( [ * | <field_key> ] )) FROM_clause [WHERE_clause] GROUP_BY_clause [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

The advanced syntax requires a GROUP BY time() clause and a nested InfluxQL function. The query first calculates the results for the nested function at the specified GROUP BY time() interval and then applies the FLOOR() function to those results.

FLOOR() supports the following nested functions: COUNT(), MEAN(), MEDIAN(), MODE(), SUM(), FIRST(), LAST(), MIN(), MAX(), and PERCENTILE().

Examples

SELECT FLOOR(MEAN("water_level")) FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica' GROUP BY time(12m)

HISTOGRAM()

InfluxQL does not currently support histogram generation. For information about creating histograms with data stored in InfluxDB, see Flux’s histogram() function.

LN()

Returns the natural logarithm of the field value.

Syntax

SELECT LN( [ * | <field_key> ] ) FROM_clause [WHERE_clause] [GROUP_BY_clause] [ORDER_BY_clause] [LIMIT_clause] [OFFSET_clause] [SLIMIT_clause] [SOFFSET_clause]

LN(field_key)
Returns the natural logarithm of field values associated with the field key.

LN(*)
Returns the natural logarithm of field values associated with each field key in the measurement.

LN() supports int64 and float64 field value data types.

Supports GROUP BY clauses that group by tags but not GROUP BY clauses that group by time. To use LN() with a GROUP BY time() clause, see Advanced syntax.

Examples

The examples below use the following subsample of the NOAA water sample data:

SELECT "water_level" FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'

SELECT LN("water_level") FROM "h2o_feet" WHERE time >= '2019-08-18T00:00:00Z' AND time <= '2019-08-18T00:30:00Z' AND "location" = 'santa_monica'