huaxingao commented on a change in pull request #28277: URL: https://github.com/apache/spark/pull/28277#discussion_r414311098
########## File path: docs/sql-ref-identifier.md ########## @@ -0,0 +1,76 @@ +--- +layout: global +title: Identifiers +displayTitle: Identifiers +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 + +An identifier is a string used to identify a database object such as a table, view, schema, column, etc. Spark SQL has regular identifiers and delimited identifiers, which are enclosed within backticks. When `spark.sql.caseSensitive` is set to false (default behavior since Spark 2.4), both regular identifiers and delimited identifiers are case-insensitive. Review comment: Sure. Will update. ########## File path: docs/sql-ref-identifier.md ########## @@ -0,0 +1,76 @@ +--- +layout: global +title: Identifiers +displayTitle: Identifiers +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 + +An identifier is a string used to identify a database object such as a table, view, schema, column, etc. Spark SQL has regular identifiers and delimited identifiers, which are enclosed within backticks. When `spark.sql.caseSensitive` is set to false (default behavior since Spark 2.4), both regular identifiers and delimited identifiers are case-insensitive. + +### Syntax + +#### Regular Identifier + +{% highlight sql %} +{ letter | digit | '_' } [ , ... ] +{% endhighlight %} +Note: If `spark.sql.ansi.enabled` is set to true, ANSI SQL reserved keywords cannot be used as identifiers. For more details, please refer to [ANSI Compliance](sql-ref-ansi-compliance.html) for a complete list of the keywords. + +#### Delimited Identifier + +{% highlight sql %} +`c [ ... ]` +{% endhighlight %} + +### Parameters + +<dl> + <dt><code><em>letter</em></code></dt> + <dd> + Any letter from A-Z or a-z. + </dd> +</dl> +<dl> + <dt><code><em>digit</em></code></dt> + <dd> + Any numeral from 0 to 9. + </dd> +</dl> +<dl> + <dt><code><em>c</em></code></dt> + <dd> + Any character from the character set. Use <code>`</code> to escape special characters (e.g., <code>`</code>). + </dd> +</dl> + +### Examples + +{% highlight sql %} +-- This CREATE TABLE fails because of the illegal identifier name a.b +CREATE TABLE test (a.b int); + +-- This CREATE TABLE works +CREATE TABLE test (`a.b` int); + +-- This CREATE TABLE fails +CREATE TABLE test1 (`a`b` int); Review comment: Yes. This throws ParseException. Do you want me to change L71 to ```-- This CREATE TABLE fails with ParseException```? ---------------------------------------------------------------- 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
