102 High-Function Business Intelligence in e-business
The function is applied to the set of numeric pairs derived from the argument
values (
expression 1,expression2
) by the elimination of all pairs for which either
expression1
or
expression2
is null.
? A null result implies the input set is empty.
? When the result is not null, it will be between minus one and one.
? A zero value means the two expressions are not linearly related.
? A minus one or a plus one mean they are linearly perfectly related.
An example of correlation is shown in, “CORRELATION examples” on page 112.
3.2.3 COUNT
The COUNT function counts the number of rows or values in a set of rows or
values. A row that includes only NULL values is included in the count, thus the
result cannot be null. The result is a large integer.
The result is the number of rows in the set.
3.2.4 COUNT_BIG
The COUNT_BIG function counts the number of rows or values in a set of rows
or values. It functions the same as COUNT except that the result can be greater
than the maximum value of integer. The result data type of COUNT_BIG is a
decimal with precision 31 and scale 0. Nulls are treated like they are in COUNT.
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