December 2002
Intermediate to advanced
928 pages
85h 29m
English
COVAR_POP (expr1,expr2) [OVER (analytic_clause)]
Computes the population covariance of a set of number pairs provided by expr1 and expr2. Both expr1 and expr2 must return numbers. After eliminating pairs of exp1 and exp2 where either is NULL, Oracle makes the following calculation.
(SUM (expr1*expr2) - SUM (expr2) * SUM (expr1) /n) /n
where n is the number of rows returned.