EQL supports the following aggregation functions.
Function | Description |
---|---|
AVG | Computes the arithmetic mean value for a field. |
COUNT | Counts the number of records with valid non-NULL values in a field for each GROUP BY result. |
COUNTDISTINCT | Counts the number of unique, valid non-NULL values in a field for each GROUP BY result. |
MAX | Finds the maximum value for a field. |
MIN | Finds the minimum value for a field. |
MEDIAN | Finds the median value for a field.
Note that the EQL definition of
MEDIAN differs from the normal statistical
definition when EQL is computing the median of an even number of numbers. That
is, given an input relation containing
{1,2,3,4}, the following query:
RETURN results AS SELECT MEDIAN(a) AS med GROUPproduces the relation { <med:3> }. According to the normal statistical definition, the statistical median of the set {1, 2, 3, 4} should be the mean of the two elements in the middle of the sorted set, or 2.5. |
STDDEV | Computes the standard deviation for a field. |
ARB | Selects an arbitrary but consistent value from the set of values in a field. |
SUM | Computes the sum of field values. |
VARIANCE | Computes the variance (that is, the square of the standard deviation) for a field. |