gengliangwang commented on a change in pull request #31982: URL: https://github.com/apache/spark/pull/31982#discussion_r604612597
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/TryCast.scala ########## @@ -0,0 +1,85 @@ +/* + * 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. + */ + +package org.apache.spark.sql.catalyst.expressions + +import org.apache.spark.sql.catalyst.expressions.codegen._ +import org.apache.spark.sql.catalyst.expressions.codegen.Block._ +import org.apache.spark.sql.types.DataType + +/** + * A special version of [[AnsiCast]]. It performs the same operation (i.e. converts a value of + * one data type into another data type), but returns a NULL value instead of raising an error + * when the conversion can not be performed. + * + * When cast from/to timezone related types, we need timeZoneId, which will be resolved with + * session local timezone by an analyzer [[ResolveTimeZone]]. + */ +@ExpressionDescription( + usage = "_FUNC_(expr AS type) - Casts the value `expr` to the target data type `type`. " + + "This expression is identical to CAST with configuration `spark.sql.ansi.enabled` as " + + "true, except it returns NULL instead of raising an error. Note that the behavior of this " + + "expression doesn't depend on configuration `spark.sql.ansi.enabled`.", + examples = """ + Examples: + > SELECT _FUNC_('10' as int); + 10 + > SELECT _FUNC_(1234567890123L as int); + null + """, + since = "3.2.0", + group = "conversion_funcs") Review comment: Actually I plan to create docs for both CAST and TRY_CAST, even with ANSI CAST. Grouping them into one section. I have created https://issues.apache.org/jira/browse/SPARK-34917 and https://issues.apache.org/jira/browse/SPARK-34918 -- 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
