maropu commented on a change in pull request #31010: URL: https://github.com/apache/spark/pull/31010#discussion_r616621413
########## File path: docs/sql-ref-syntax-qry-select-transform.md ########## @@ -0,0 +1,235 @@ +--- +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 query specification +to transform the inputs by running a user-specified command or script. + +### Syntax + +```sql +SELECT TRANSFORM ( expression [ , ... ] ) + [ ROW FORMAT row_format ] + [ RECORDWRITER record_writer_class ] + USING command_or_script [ AS ( [ col_name [ col_type ] ] [ , ... ] ) ] + [ ROW FORMAT row_format ] + [ RECORDREADER record_reader_class ] + +row_format: + SERDE serde_class [ WITH SERDEPROPERTIES (k1=v1, k2=v2, ... ) ] + | DELIMITED [ FIELDS TERMINATED BY fields_terminated_char [ ESCAPED BY escaped_char ] ] + [ COLLECTION ITEMS TERMINATED BY collection_items_terminated_char ] + [ MAP KEYS TERMINATED BY map_key_terminated_char ] + [ LINES TERMINATED BY row_terminated_char ] + [ NULL DEFINED AS null_char ] +``` + +### Parameters + +* **expression** + + Specifies a combination of one or more values, operators and SQL functions that results in a value. + +* **row_format** + + Otherwise, uses the `DELIMITED` clause to specify the native SerDe and state the delimiter, escape character, null character and so on. Review comment: @AngersZhuuuu Where is the statement "Uses the `SERDE` clause to specify a custom SerDe for one table. "? -- 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: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
