REGR_SXY()

Aggregate. Returns the sum of products of the dependent and independent variables. The REGR_SXY function can be used to evaluate the statistical validity of a regression model.

Syntax

REGR_SXY( dependent-expression , independent-expression )

Parameters
dependent-expression	The variable that is affected by the independent variable.
independent-expression	The variable that influences the outcome.

This function converts its arguments to DOUBLE, performs the computation in double-precision floating point, and returns a DOUBLE as the result. If the function is applied to an empty set, then it returns NULL. The function is applied to the set of (dependent-expression and independent-expression) pairs after eliminating all pairs for which either dependent-expression or independent-expression is NULL. The function is computed simultaneously during a single pass through the data. After eliminating NULL values, the following computation is then made, where x represents the dependent-expression and y represents the independent-expression:

REGR_COUNT( x, y ) * COVAR_POP( x, y )

SQL/2003 SQL foundation feature (T621) outside of core SQL.

The following example returns the sum of products of the dependent and independent variables.

With a GROUP BY clause:

SELECT REGR_SXY()( Salary, ( 2008 - YEAR( BirthDate ) ) ) 
FROM Employees
group by depart_ID

With a window:

SELECT REGR_SXY()( Salary, ( 2008 - YEAR( BirthDate ) ) ) 
FROM Employees
KEEP 10 ROWS