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x_intercept()

Calculate the x-intercept from a two-dimensional statistical aggregate

Since 1.3.0

Calculate the x intercept from a two-dimensional statistical aggregate. The calculation uses the standard least-squares fitting for linear regression.

Samples

Calculate the x intercept from independent variable y and dependent variable x for each 15-minute time bucket:

SELECT
    id,
    time_bucket('15 min'::interval, ts) AS bucket,
    x_intercept(stats_agg(y, x)) AS summary
FROM foo
GROUP BY id, time_bucket('15 min'::interval, ts)

Arguments

The syntax is:

x_intercept(
  summary StatsSummary2D
) RETURNS DOUBLE PRECISION

Name	Type	Default	Required	Description
summary	StatsSummary2D	-	✔	The statistical aggregate produced by a `stats_agg` call

Returns

Column	Type	Description
intercept	DOUBLE PRECISION	The x intercept of the least-squares fit line