Categories:

Aggregate Functions (Linear Regression) , Window Functions

REGR_SLOPE

Returns the slope of the linear regression line for non-null pairs in a group. It is computed for non-null pairs using the following formula:

COVAR_POP(x,y) / VAR_POP(x)

Where x is the independent variable and y is the dependent variable.

Syntax

REGR_SLOPE(y, x)

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.

Important

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

Returns

The data type of the returned value is FLOAT.

Usage Notes

  • DISTINCT is not supported for this function.

Examples

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, regr_slope(v, v2) from aggr group by k;

---+-------------------+
 k | regr_slope(v, v2) |
---+-------------------+
 1 | [NULL]            |
 2 | 0.831408776       |
---+-------------------+