MarkLogic 12 EA 2 Product Documentation

op.hasGroupKey

op.hasGroupKey(
   outputColumn as String,
   column as columnIdentifier
) as aggregatedef

Summary

This aggregate function adds a flag to a grouped row specifying whether a column acted as a grouping key for the row.

The flag column has a value of 0 in result rows belonging to a group that has the group key and a value of 1 in other result rows. The aggregate is useful for the prototype.groupByUnion function in cases where the grouping key is nullable and, thus, null values in the grouping key column are insufficient to distinguish rows grouped on a null value from rows that don't belong to a group with the grouping key.

See Also

• prototype.groupByUnion

Example

const op = require('/MarkLogic/optic');

op.fromView('main', 'expenses')
   .groupByUnion(
       [op.group(), op.group(['Category', 'Location'])],
       [op.hasGroupKey('Category'), op.hasGroupKey('Location'), op.sum("TotalAmount", "Amount")]
       )
   .orderBy(['Category', 'Location'])
   .result();