- Categories:
Aggregate Functions (General) , Window Functions (General, Window frame)
VARIANCE_POP¶
Returns the population variance of non-NULL records in a group. If all records inside a group are NULL, a NULL is returned.
- Aliases:
Syntax¶
Aggregate function
VARIANCE_POP( [ DISTINCT ] <expr1> )
Window function
VARIANCE_POP( [ DISTINCT ] <expr1> ) OVER (
[ PARTITION BY <expr2> ]
[ ORDER BY <expr3> [ ASC | DESC ] [ <window_frame> ] ]
)
For details about window_frame
syntax, see Window Frame Syntax and Usage.
Arguments¶
expr1
The
expr1
should evaluate to one of the numeric data types.expr2
This is the optional expression to partition by.
expr3
This is the optional expression to order by within each partition.
Returns¶
The data type of the returned value is NUMBER(<precision>, <scale>)
. The scale depends upon the values being processed.
Usage Notes¶
When passed a VARCHAR expression, this function implicitly casts the input to floating point values. If the cast cannot be performed, an error is returned.
When this function is called as a window function (i.e. with an OVER clause):
If the OVER clause contains an ORDER BY subclause, then:
A window frame is required. If no window frame is specified explicitly, then the ORDER BY implies a cumulative window frame:
RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
For information about window frames, including syntax and examples, see Window Frame Syntax and Usage.
For information about implied window frames, see also Window Frame Usage Notes.
Using the keyword DISTINCT inside the window function is prohibited and results in a compile-time error.