regr_count ​

Counts input pairs for which both numeric arguments are non-NULL. Use it to find the number of observations admitted by the covariance, correlation and regression aggregates.

Syntax

regr_count(y, x)

Arguments

• y — The dependent numeric variable.
• x — The independent numeric variable.

A row with either argument NULL is excluded. Nonfinite numeric pairs are counted.

Returned value

A nonnegative INTEGER pair count. Empty input, or input with no complete pairs, returns 0.

Examples

Counting complete observations

CREATE TABLE measurements (hour INTEGER, reading INTEGER);
INSERT INTO measurements VALUES (1, 3), (2, 5), (3, NULL), (NULL, 9);

SELECT count(*) AS rows,
       count(hour) AS hours,
       count(reading) AS readings,
       regr_count(reading, hour) AS complete_pairs
FROM measurements
FORMAT csv;

4,3,3,2

No complete observations

CREATE TABLE incomplete_measurements (hour INTEGER, reading INTEGER);
INSERT INTO incomplete_measurements VALUES (1, NULL), (NULL, 5);

SELECT regr_count(reading, hour)
FROM incomplete_measurements
FORMAT csv;

0

See regr_slope, covar_pop and corr for calculations over the admitted pairs.