AngersZhuuuu commented on a change in pull request #31010: URL: https://github.com/apache/spark/pull/31010#discussion_r613962196
########## File path: docs/sql-ref-syntax-qry-select-transform.md ########## @@ -0,0 +1,244 @@ +--- +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 specified script. Users can plug in their own custom +scripts in the data stream by using features natively supported in the Spark SQL. + +### Syntax + +```sql +SELECT TRANSFORM ( named_expression [ , ... ] ) + [ ROW FORMAT row_format ] + [ RECORDWRITER record_writer_class ] + USING 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 + +* **named_expression** + + An expression with an assigned name. In general, it denotes a column expression. + + **Syntax:** `expression [AS] [alias]` + +* **row_format** + + Spark uses the `SERDE` clause to specify a custom SerDe for one table. Otherwise, use the `DELIMITED` clause to use the native SerDe and specify the delimiter, escape character, null character and so on. + +* **SERDE** + + Specifies a custom SerDe for one table. + +* **serde_class** + + Specifies a fully-qualified class name of a custom SerDe. + +* **DELIMITED** + + The `DELIMITED` clause can be used to specify the native SerDe and state the delimiter, escape character, null character and so on. + +* **FIELDS TERMINATED BY** + + Used to define a column separator. + +* **COLLECTION ITEMS TERMINATED BY** + + Used to define a collection item separator. + +* **MAP KEYS TERMINATED BY** + + Used to define a map key separator. + +* **LINES TERMINATED BY** + + Used to define a row separator. + +* **NULL DEFINED AS** + + Used to define the specific value for NULL. + +* **ESCAPED BY** + + Used for escape mechanism. + +* **RECORDWRITER** + + Specifies a fully-qualified class name of a custom RecordWriter. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordWriter`. + +* **RECORDREADER** + + Specifies a fully-qualified class name of a custom RecordReader. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordReader`. + +* **script** + + Specifies a command to process data. Review comment: change to ``` Specifies a command or a path to script to process data. ``` ########## File path: docs/sql-ref-syntax-qry-select-transform.md ########## @@ -0,0 +1,244 @@ +--- +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 specified script. Users can plug in their own custom +scripts in the data stream by using features natively supported in the Spark SQL. + +### Syntax + +```sql +SELECT TRANSFORM ( named_expression [ , ... ] ) + [ ROW FORMAT row_format ] + [ RECORDWRITER record_writer_class ] + USING 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 + +* **named_expression** + + An expression with an assigned name. In general, it denotes a column expression. + + **Syntax:** `expression [AS] [alias]` + +* **row_format** + + Spark uses the `SERDE` clause to specify a custom SerDe for one table. Otherwise, use the `DELIMITED` clause to use the native SerDe and specify the delimiter, escape character, null character and so on. + +* **SERDE** + + Specifies a custom SerDe for one table. + +* **serde_class** + + Specifies a fully-qualified class name of a custom SerDe. + +* **DELIMITED** + + The `DELIMITED` clause can be used to specify the native SerDe and state the delimiter, escape character, null character and so on. + +* **FIELDS TERMINATED BY** + + Used to define a column separator. + +* **COLLECTION ITEMS TERMINATED BY** + + Used to define a collection item separator. + +* **MAP KEYS TERMINATED BY** + + Used to define a map key separator. + +* **LINES TERMINATED BY** + + Used to define a row separator. + +* **NULL DEFINED AS** + + Used to define the specific value for NULL. + +* **ESCAPED BY** + + Used for escape mechanism. + +* **RECORDWRITER** + + Specifies a fully-qualified class name of a custom RecordWriter. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordWriter`. + +* **RECORDREADER** + + Specifies a fully-qualified class name of a custom RecordReader. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordReader`. + +* **script** + + Specifies a command to process data. + +### SerDe behavior + +Spark uses Hive Serde `org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe` by default, columns will be transformed Review comment: done -- 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]
