Specifies the number of output key-value pair columns to produce after unpivoting.
This optional parameter is used to create multiple sets of key-value pair columns in the output. The columns listed in the
col parameter are placed into each pair of output key-value columns sequentially. After all key-value pair columns are filled in a record, the next column is placed into the first key-value pair column of the next record.
By default, this value is
1, meaning that each column specified in the transform is rendered into a new record in a single pair of key-value columns.