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SQL Anywhere 10.0.1 » SQL Anywhere Server - SQL Reference » SQL Functions » Alphabetical list of functions

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REGR_AVGX function [Aggregate]


Computes the average of the independent variable of the regression line.

Syntax 1

REGR_AVGX( dependent-expression , independent-expression )

Syntax 2

REGR_AVGX( dependent-expression , independent-expression )
OVER (
window-spec )

window-spec : see Syntax 2 instructions in the Usage section below

Parameters

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

independent-expression    The variable that influences the outcome.

Remarks

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 y represents the independent-expression:

AVG( y )

For more information about the statistical computation performed, see Mathematical formulas for the aggregate functions.

Syntax 2 represents usage as a window function in a SELECT statement. As such, elements of window-spec can be specified either in the function syntax (inline), or in conjunction with a WINDOW clause in the SELECT statement. See the window-spec definition provided in WINDOW clause.

For more information about using window functions in SELECT statements, including working examples, see Window functions.

See also
Standards and compatibility
Example

The following example calculates the average of the dependent variable, employee age.

SELECT REGR_AVGX( Salary, ( YEAR( NOW() ) - YEAR( BirthDate ) ) )
FROM Employees ;