ClickHouse/docs/en/sql-reference/functions/time-series-functions.md

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/en/sql-reference/functions/time-series-functions	172	Time Series

Time Series Functions

Below functions are used for time series analysis.

seriesPeriodDetectFFT

Finds the period of the given time series data using FFT FFT - Fast Fourier transform

Syntax

seriesPeriodDetectFFT(series);

Arguments

• series - An array of numeric values

Returned value

• A real value equal to the period of time series
• Returns NAN when number of data points are less than four.

Type: Float64.

Examples

Query:

SELECT seriesPeriodDetectFFT([1, 4, 6, 1, 4, 6, 1, 4, 6, 1, 4, 6, 1, 4, 6, 1, 4, 6, 1, 4, 6]) AS print_0;

Result:

┌───────────print_0──────┐
│                      3 │
└────────────────────────┘

SELECT seriesPeriodDetectFFT(arrayMap(x -> abs((x % 6) - 3), range(1000))) AS print_0;

Result:

┌─print_0─┐
│       6 │
└─────────┘