Aggregation Functions

Aggregation functions are statistical functions that are used with a set of values. They return one value that is characteristic of such set.

The following aggregation functions are listed in the table below:

Aggregation kind							Comment
Sum		•	•				It sums up values of all cells in the column.
Count	•	•	•	•	•	•	It displays total number of records in the data set, including null records and records without a value (<null>).
Minimum	•	•	•	•	•	•	It shows the minimum value by column. The null records are not included into the aggregation, with the exception of String type where the null record is the minimum one. Records with <null> are not included into the aggregation.
Maximum	•	•	•	•	•	•	It shows the maximum value by column. For String type the order to maximum is as follows: "Null value → Characters → Digits → the lowercase Latin alphabet → the uppercase Latin alphabet.
Average		•	•				It shows the average value of all column cells. The fields that are not empty and <null> are included into calculations.
Median		•	•				It shows the median value by column. The fields that are included into the aggregation are as for the Average aggregation.
Standard deviation		•	•				It shows the mean-square deviation by column. The fields that are included into the aggregation are as for the Average aggregation.
Count of unique	•	•	•	•	•	•	It displays the count of unique record values. The records with the null value, with <null> value or the value that does not match the data type are not taken into account in the calculation process. With the exception of String data type where only the records with <null> value are not taken into account.
Null count	•	•	•	•	•	•	It displays the number of records with the null values, <null> value or the values that do not match the data type. With the exception of String data type where the records with <null> value are considered to be null.
The first	•	•	•	•	•	•	It shows the value of the first record in the data set.
The last	•	•	•	•	•	•	It shows the value of the last record in the data set.

Note: The Variable Data type follows the aggregation method of the data type that has been selected in the wizard before.