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

COVAR_POP function [Aggregate] Next Page

COVAR_SAMP function [Aggregate]


Returns the sample covariance of a set of number pairs.

Syntax 1

COVAR_SAMP( dependent-expression, independent-expression )

Syntax 2

COVAR_SAMP( 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.

Both dependent-expression and independent-expression are numeric. The function is applied to the set of (dependent-expression, independent-expression) pairs after eliminating all pairs for which either dependent-expression or independent-expression is NULL.

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 returns the value 74782.94600540561.

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