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Posted to reviews@spark.apache.org by GitBox <gi...@apache.org> on 2021/04/08 14:39:31 UTC
[GitHub] [spark] AngersZhuuuu commented on a change in pull request #31010: [SPARK-33976][SQL][DOCS] Add a SQL doc page for a TRANSFORM clause
AngersZhuuuu commented on a change in pull request #31010:
URL: https://github.com/apache/spark/pull/31010#discussion_r609773608
##########
File path: docs/sql-ref-syntax-qry-select-transform.md
##########
@@ -0,0 +1,262 @@
+---
+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 named_expression [ , ... ] | REDUCE named_expression [ , ... ] }
+ [ rowFormat ]
+ [ RECORDWRITER recordWriter_class ]
+ USING script [ AS ( [ col_name [ col_type ]] [ , ... ] ) ]
+ [ rowFormat ]
+ [ RECORDREADER recordReader_class ]
+```
+
+While `rowFormat` are defined as
+```sql
+{ ROW FORMAT SERDE serde_class [ WITH SERDEPROPERTIES serde_props ] |
+ROW FORMAT DELIMITED
+ [ FIELDS TERMINATED BY fields_terminated_char [ ESCAPED BY escapedBy ] ]
+ [ COLLECTION ITEMS TERMINATED BY collectionItemsTerminatedBy ]
+ [ MAP KEYS TERMINATED BY keysTerminatedBy ]
+ [ LINES TERMINATED BY linesSeparatedBy ]
+ [ NULL DEFINED AS nullDefinedAs ] }
+```
+
+### Parameters
+
+* **named_expression**
+
+ An expression with an assigned name. In general, it denotes a column expression.
+
+ **Syntax:** `expression [AS] [alias]`
+
+* **row_format**
+
+ Use 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.
+
+* **SERDEPROPERTIES**
+
+ A list of key-value pairs that is used to tag the SerDe definition.
+
+* **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.
+
+* **RECORDREADER**
+
+ Specifies a custom RecordReader for one table.
+
+* **RECORDWRITER**
+
+ Specifies a custom RecordWriter for one table.
+
+* **recordReader_class**
+
+ Specifies a fully-qualified class name of a custom RecordReader. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordReader`.
+
+* **recordWriter_class**
+
+ Specifies a fully-qualified class name of a custom RecordWriter. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordWriter`.
+
+* **script**
+
+ Specifies a command to process data.
+
+### SERDE behavior
Review comment:
Done
##########
File path: docs/sql-ref-syntax-qry-select-transform.md
##########
@@ -0,0 +1,262 @@
+---
+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 named_expression [ , ... ] | REDUCE named_expression [ , ... ] }
+ [ rowFormat ]
+ [ RECORDWRITER recordWriter_class ]
+ USING script [ AS ( [ col_name [ col_type ]] [ , ... ] ) ]
+ [ rowFormat ]
+ [ RECORDREADER recordReader_class ]
+```
+
+While `rowFormat` are defined as
+```sql
+{ ROW FORMAT SERDE serde_class [ WITH SERDEPROPERTIES serde_props ] |
+ROW FORMAT DELIMITED
+ [ FIELDS TERMINATED BY fields_terminated_char [ ESCAPED BY escapedBy ] ]
+ [ COLLECTION ITEMS TERMINATED BY collectionItemsTerminatedBy ]
+ [ MAP KEYS TERMINATED BY keysTerminatedBy ]
+ [ LINES TERMINATED BY linesSeparatedBy ]
+ [ NULL DEFINED AS nullDefinedAs ] }
+```
+
+### Parameters
+
+* **named_expression**
+
+ An expression with an assigned name. In general, it denotes a column expression.
+
+ **Syntax:** `expression [AS] [alias]`
+
+* **row_format**
+
+ Use 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.
+
+* **SERDEPROPERTIES**
+
+ A list of key-value pairs that is used to tag the SerDe definition.
+
+* **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.
+
+* **RECORDREADER**
+
+ Specifies a custom RecordReader for one table.
+
+* **RECORDWRITER**
+
+ Specifies a custom RecordWriter for one table.
+
+* **recordReader_class**
+
+ Specifies a fully-qualified class name of a custom RecordReader. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordReader`.
+
+* **recordWriter_class**
+
+ Specifies a fully-qualified class name of a custom RecordWriter. A default value is `org.apache.hadoop.hive.ql.exec.TextRecordWriter`.
+
+* **script**
+
+ Specifies a command to process data.
+
+### SERDE behavior
+
+In default format we use Hive Serde `org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe`, columns will be transformed
Review comment:
Done
##########
File path: docs/sql-ref-syntax-qry-select-transform.md
##########
@@ -0,0 +1,262 @@
+---
+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 named_expression [ , ... ] | REDUCE named_expression [ , ... ] }
+ [ rowFormat ]
+ [ RECORDWRITER recordWriter_class ]
+ USING script [ AS ( [ col_name [ col_type ]] [ , ... ] ) ]
+ [ rowFormat ]
+ [ RECORDREADER recordReader_class ]
+```
+
+While `rowFormat` are defined as
+```sql
+{ ROW FORMAT SERDE serde_class [ WITH SERDEPROPERTIES serde_props ] |
+ROW FORMAT DELIMITED
+ [ FIELDS TERMINATED BY fields_terminated_char [ ESCAPED BY escapedBy ] ]
+ [ COLLECTION ITEMS TERMINATED BY collectionItemsTerminatedBy ]
+ [ MAP KEYS TERMINATED BY keysTerminatedBy ]
+ [ LINES TERMINATED BY linesSeparatedBy ]
+ [ NULL DEFINED AS nullDefinedAs ] }
+```
+
+### Parameters
+
+* **named_expression**
+
+ An expression with an assigned name. In general, it denotes a column expression.
+
+ **Syntax:** `expression [AS] [alias]`
+
+* **row_format**
+
+ Use 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.
Review comment:
Done
##########
File path: docs/sql-ref-syntax-qry-select-transform.md
##########
@@ -0,0 +1,262 @@
+---
+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 named_expression [ , ... ] | REDUCE named_expression [ , ... ] }
+ [ rowFormat ]
+ [ RECORDWRITER recordWriter_class ]
+ USING script [ AS ( [ col_name [ col_type ]] [ , ... ] ) ]
+ [ rowFormat ]
+ [ RECORDREADER recordReader_class ]
+```
+
+While `rowFormat` are defined as
+```sql
+{ ROW FORMAT SERDE serde_class [ WITH SERDEPROPERTIES serde_props ] |
+ROW FORMAT DELIMITED
Review comment:
Done
##########
File path: docs/sql-ref-syntax-qry-select-transform.md
##########
@@ -0,0 +1,262 @@
+---
+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 named_expression [ , ... ] | REDUCE named_expression [ , ... ] }
+ [ rowFormat ]
+ [ RECORDWRITER recordWriter_class ]
+ USING script [ AS ( [ col_name [ col_type ]] [ , ... ] ) ]
Review comment:
Done
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