Syntax: How to Calculate Running Average Between the Current and a Prior Value of a Field
RUNNING_AVE(field, reset_key, lower)
where:
- field
-
Numeric
The field to be used in the calculation.
- reset_key
-
Identifies the point at which the running average restarts. Valid values are:
- The name of a sort field in the request.
- PRESET, which uses the value of the PARTITION_ON parameter, as described in Specify the Partition Size for Simplified Statistical Functions.
- TABLE, which indicates that there is no break on a sort field.
Note: The values used in the calculations depend on the sort sequence (ascending or descending) specified in the request. Be aware that displaying a date or time dimension in descending order may produce different results than those you may expect.
- lower
-
Is the starting point in the partition for the running average. Valid values are:
- A negative number, which identifies the offset from the current row.
- B, which specifies the beginning of the sort group.
Example: Calculating a Running Average
The following request calculates a running average of QUANTITY_SOLD within the PRODUCT_CATEGORY sort field, always starting from the beginning of the sort break.
TABLE FILE wf_retail_lite
SUM QUANTITY_SOLD
COMPUTE RAVE = RUNNING_AVE(QUANTITY_SOLD,PRODUCT_CATEGORY,B);
BY PRODUCT_CATEGORY
BY PRODUCT_SUBCATEG
ON TABLE SET PAGE NOLEAD
ON TABLE SET STYLE *
GRID=OFF,$
ENDSTYLE
END
The output is shown in the following image. The first value for RAVE is the value in the Accessories category for Quantity Sold, as there is no prior value. The second value for RAVE is the average of the values for Headphones and Charger, the third is the average of the values for Headphones, Charger, and Universal Remote Controls. Then, the calculations start over for Camcorder, which is the reset point.
