Projections

Projection functions change the shape of the data. The following projection functions are available:

  • select - map each element in the stream to a new element, for instance with less fields or with calculated fields.

  • groupby - map elements with the same value for the group by fields to a new element.

  • count - counts the number of elements in the stream, when used with a parameter counts the number of non-null/true fields for the parameter value.

  • min - minimum value for the paramater value

  • max - maximum value for the paramater value

  • avg - average value for the paramater value

The count, min, max and avg functions can also be used inside a group by.