Categories:

Aggregate Functions (Linear Regression) , Window Functions

REGR_COUNT

Returns the number of non-null number pairs in a group.

Syntax

Aggregate function

REGR_COUNT(y, x)

Window function

REGR_COUNT(y, x) OVER ( [ PARTITION BY <expr3> ] )

Arguments

y

The dependent variable. This must be an expression that can be evaluated to a numeric type.

x

The independent variable. This must be an expression that can be evaluated to a numeric type.

expr3

This is the optional expression used to group rows into partitions.

Important

Note the order of the arguments; the dependent variable is first.

Usage Notes

  • DISTINCT is not supported for this function.

  • When used as a window function:

    • This function does not support:

      • ORDER BY sub-clause in the OVER() clause.

      • Window frames.

Examples

Show the number of pairs in each group, and the number of those pairs in which neither member is NULL.

create or replace table aggr(k int, v decimal(10,2), v2 decimal(10, 2));
insert into aggr values(1, 10, null);
insert into aggr values(2, 10, 11), (2, 20, 22), (2, 25,null), (2, 30, 35);

select k, count(*), regr_count(v, v2) from aggr group by k;

---+----------+-------------------+
 k | count(*) | regr_count(v, v2) |
---+----------+-------------------+
 1 |      1   |            0      |
 2 |      4   |            3      |
---+----------+-------------------+