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(warning) PLEASE NOTE: This documentation applies to Pentaho 8.1 and earlier. For Pentaho 8.2 and later, see Memory Group By on the Pentaho Enterprise Edition documentation site.

Description

This step builds aggregates in a group by fashion and does not require a sorted input since it processes all rows within memory. When the number of rows is too large to fit into memory, you need to use the combination of the Sort rows and Group by steps.

Options

Option

Definition

Step name

The name of this step as it appears in the transformation workspace.

Always give back a result row

If you enable this option, the Group By step will always give back a result row, even if there is no input row. 
This can be useful if you want to count the number of rows.  Without this option you would never get a count of zero (0).

The field that make up the group

After retrieving fields using the Get Fields button, designate the fields to include in the group. See the Group be step for more details.

Aggregates

After retrieving fields using the Get lookup fields button, designate the fields to include in the group. See the Group be step for more details.

Metadata Injection Support (7.x and later)

All fields of this step support metadata injection. You can use this step with ETL Metadata Injection to pass metadata to your transformation at runtime.

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