Description of the illustration covar_samp.gif

See Also:

"Analytic Functions" for information on syntax, semantics, and restrictions`COVAR_SAMP`

returns the sample covariance of a set of number pairs. You can use it as an aggregate or analytic function.

This function takes as arguments any numeric datatype or any nonnumeric datatype that can be implicitly converted to a numeric datatype. Oracle determines the argument with the highest numeric precedence, implicitly converts the remaining arguments to that datatype, and returns that datatype.

See Also:

Table 2-10, "Implicit Type Conversion Matrix" for more information on implicit conversion and "Numeric Precedence" for information on numeric precedenceOracle Database applies the function to the set of (`expr1`

, `expr2`

) pairs after eliminating all pairs for which either `expr1`

or `expr2`

is null. Then Oracle makes the following computation:

(SUM(expr1 * expr2) - SUM(expr1) * SUM(expr2) / n) / (n-1)

where `n`

is the number of (`expr1`

, `expr2`

) pairs where neither `expr1`

nor `expr2`

is null.

The function returns a value of type `NUMBER`

. If the function is applied to an empty set, then it returns null.

Please refer to the aggregate example for COVAR_POP.

Please refer to the analytic example for COVAR_POP.