AngersZhuuuu commented on a change in pull request #31010: URL: https://github.com/apache/spark/pull/31010#discussion_r613916069
########## File path: docs/sql-ref-syntax-qry-select-transform.md ########## @@ -0,0 +1,247 @@ +--- +layout: global +title: TRANSFORM +displayTitle: TRANSFORM +license: | + 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. +--- + +### Description + +The `TRANSFORM` clause is used to specify a Hive-style transform (`SELECT TRANSFORM`/`MAP`/`REDUCE`) +query specification to transform the input by running a specified script. Users can +plug in their own custom mappers or reducers in the data stream by using features natively supported +in the Spark SQL. In order to run a custom mapper script `map_script` or a custom +reducer script `reduce_script` the user can issue the command which uses the `TRANSFORM` +clause to embed the mapper or the reducer scripts. + +### Syntax + +```sql +{ SELECT TRANSFORM ( named_expression [ , ... ] ) | { MAP | REDUCE } named_expression [ , ... ] } Review comment: how about current? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
