Learn about rollup analysis functions
- Last UpdatedJan 08, 2025
- 2 minute read
- PI System
- PI Server 2018
- PI Server
You can specify one or more of the functions listed below to calculate statistics on the input attributes in a rollup analysis.
-
Bad input attributes are omitted from rollup analysis. For example, if you have 5 attributes that match the criteria but 1 is a bad value, Count function will return 4.
-
Input value types numeric, DateTime and Enumeration value are supported for functions Minimum, Maximum, and Count. Function Average takes numeric and DateTime value types. Input values for all other functions must be of numeric value type.
Function
Description
Supported data types
Sum
The sum of values from selected attributes.
Numeric
Average
The average (mean) of values from two or more selected attributes.
Numeric, DateTime
Minimum
The minimum value from selected attributes.
Numeric, DateTime, Enumeration value
Maximum
The maximum value from selected attributes.
Numeric, DateTime, Enumeration value
Count
The number of attributes actually used in rollup calculations, which can differ from the total number of selected attributes. For example, an attribute containing a string value (such as a part name) might meet the selection criteria but would not participate in rollup calculations and would be excluded for Count.
Numeric, DateTime, Enumeration value
Median
The middle value of three or more values from selected attributes; for an even-numbered group of values, the average of the two middle values. An equal number of values fall above and below the median.
Numeric
Population standard deviation
The population standard deviation, which is calculated using the entire population. Useful when all values in a population are available to include as inputs for the calculation.
Numeric
Sample standard deviation
The sample standard deviation, which is calculated using values from a sample of a population. Useful to provide an estimate of the population standard deviation when it is impractical or impossible to include all population values in the calculation.
Numeric