hop-user-manual/modules/ROOT/pages/plugins/transforms/memgroupby.adoc - incubator-hop-docs - Git at Google

 ////
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you under the Apache License, Version 2.0 (the
 "License"); you may not use this file except in compliance
 with the License.  You may obtain a copy of the License at
   http://www.apache.org/licenses/LICENSE-2.0
 Unless required by applicable law or agreed to in writing,
 software distributed under the License is distributed on an
 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 KIND, either express or implied.  See the License for the
 specific language governing permissions and limitations
 under the License.
 ////
 :documentationPath: /plugins/transforms/
 :language: en_US
 :page-alternativeEditUrl: https://github.com/apache/incubator-hop/edit/master/plugins/transforms/memgroupby/src/main/doc/memgroupby.adoc

 = Memory Group By

 == Description

 The Memory Group By transform 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 transforms.

 == Options

 [width="90%", options="header"]
 |===
 |Option|Description
 |Transform name|Name of the transform this name has to be unique in a single pipeline,
 |Always give back a result row|If you enable this option, the Group By transform 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 transform 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 transform for more details.
 |===

 == Metadata Injection Support

 All fields of this transform support metadata injection. You can use this transform with ETL Metadata Injection to pass metadata to your pipeline at runtime.
	////
	Licensed to the Apache Software Foundation (ASF) under one
	or more contributor license agreements. See the NOTICE file
	distributed with this work for additional information
	regarding copyright ownership. The ASF licenses this file
	to you under the Apache License, Version 2.0 (the
	"License"); you may not use this file except in compliance
	with the License. You may obtain a copy of the License at
	http://www.apache.org/licenses/LICENSE-2.0
	Unless required by applicable law or agreed to in writing,
	software distributed under the License is distributed on an
	"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	KIND, either express or implied. See the License for the
	specific language governing permissions and limitations
	under the License.
	////
	:documentationPath: /plugins/transforms/
	:language: en_US
	:page-alternativeEditUrl: https://github.com/apache/incubator-hop/edit/master/plugins/transforms/memgroupby/src/main/doc/memgroupby.adoc

	= Memory Group By

	== Description

	The Memory Group By transform 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 transforms.

	== Options

	[width="90%", options="header"]
	\|===
	\|Option\|Description
	\|Transform name\|Name of the transform this name has to be unique in a single pipeline,
	\|Always give back a result row\|If you enable this option, the Group By transform 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 transform 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 transform for more details.
	\|===

	== Metadata Injection Support

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