SQL/MX 3.1 Reference Manual (H06.23+, J06.12+)

SQL/MX Functions and Expressions
HP NonStop SQL/MX Release 3.1 Reference Manual—663850-001
9-116
MOVINGVARIANCE Function
MOVINGVARIANCE Function
•
The MOVINGVARIANCE function is a sequence function that returns the
variance of nonnull values of a column in the current window of an intermediate
result table ordered by a SEQUENCE BY clause in a SELECT statement. See
SEQUENCE BY Clause on page 7-18.
•
MOVINGVARIANCE is an SQL/MX extension.
•
MOVINGVARIANCE (column-expression,integer-expression
•
[,max-rows])
•
•
column-expression
•
specifies a derived column determined by the evaluation of the column
expression.
•
integer-expression
•
is an SQL numeric value expression of signed data type SMALLINT or
INTEGER that specifies the current window. The current window is defined as
the current row and the previous (integer-expression - 1) rows.
•
max-rows
•
is an SQL numeric value expression of signed data type SMALLINT or
INTEGER that specifies the maximum number of rows in the current window.
•
Note these considerations for the window size:The actual value for the window
size is the minimum of integer-expression and max-rows.
•
If these conditions are met, MOVINGVARIANCE returns the same result as
RUNNINGVARIANCE:
°
The integer-expression is out of range, and max-rows is not
specified. This condition includes the case in which both integer-
expression and max-rows are larger than the result table.
°
The minimum of integer-expression and max-rows is out of range.
In this case, integer-expression could be within range, but max-rows
might be the minimum value of the two and be out of range (for example, a
negative number).
•
The number of rows is out of range if it is larger than the size of the result
table, negative, or NULL.