Definition:
In Oracle PL/SQL, the function REGR_R2 is a linear regression analytic function which takes two numeric inputs and returns a numeric output which denotes how well a regression line is fitted. Another way of stating this is that it returns the coefficient of determination, or R-squared, of the regression line. Its return value is determined based on the conditions shown below:
NULL, if VAR_POP (y) = 0
1, if VAR_POP(x) = 0 and VAR_POP(y) <> 0;
POWER(CORR (x,y), if VAR_POP (x) > 0 and VAR_POP(y) <> 0
Note that the pairs having any argument's value as NULL are eliminated, but the final result might be NULL as per the above computation.
Example Syntax:
REGR_R2(x,y)
In the syntax, 'x' is referred to as the dependent variable and 'y' is referred to as the independent variable of the Regression Line.
Example Usage:
The SQL query below uses REGR_R2 to determine the degree of fitness over regression line.
select deptno, sal, regr_r2(deptno, sal) over (partition by deptno) "REGR_R2"
from employee
/
DEPTNO SAL REGR_R2
----------- ---------- ----------
100 2300 1
100 3810 1
100 3810 1
100 8300 1
100 1
100 2300 1
110 3900 1
110 8210 1
110 2900 1
120 4500 1
120 8300 1
120 1200 1
120 3200 1
13 rows selected.
Related Links:
Related Code Snippets:
- REGR_R2 - REGR_R2 returns the coefficient of determination (also called "R-squared" or "goodness o...