maropu commented on a change in pull request #31982: URL: https://github.com/apache/spark/pull/31982#discussion_r603013688
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/TryCast.scala ########## @@ -0,0 +1,88 @@ +/* + * 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.internal.SQLConf +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 `spark.sql.ansi.enabled` as true, " + + "except it returns NULL instead of raising an error. " + + "This expression has one major difference from `cast` with `spark.sql.ansi.enabled` as true: " + + "when the source value can't be stored in the target integral(Byte/Short/Int/Long) type, " + + "`try_cast` returns null instead of returning the low order bytes of the source value.", Review comment: nit: `try_cast` => `_FUNC_`? ########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/TryCast.scala ########## @@ -0,0 +1,88 @@ +/* + * 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.internal.SQLConf +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 `spark.sql.ansi.enabled` as true, " + + "except it returns NULL instead of raising an error. " + + "This expression has one major difference from `cast` with `spark.sql.ansi.enabled` as true: " + Review comment: ditto ########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala ########## @@ -1610,6 +1610,17 @@ class AstBuilder extends SqlBaseBaseVisitor[AnyRef] with SQLConfHelper with Logg cast } + /** + * Create a [[TryCast]] expression. + */ + override def visitTryCast(ctx: TryCastContext): Expression = withOrigin(ctx) { Review comment: `visitCast` and `visitTryCast` are similar between each other, so how about merging their definition in `SqlBase.sql`? ``` | cast=(CAST | TRY_CAST) '(' expression AS dataType ')' #cast ``` ########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/TryCast.scala ########## @@ -0,0 +1,88 @@ +/* + * 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.internal.SQLConf +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 `spark.sql.ansi.enabled` as true, " + Review comment: nti: `spark.sql.ansi.enabled` -> `SQLConf.ANSI_ENABLED.key`? ########## File path: sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala ########## @@ -4118,6 +4118,26 @@ class SQLQuerySuite extends QueryTest with SharedSparkSession with AdaptiveSpark } } + test("try_cast") { Review comment: Could we move this test into `SQLQueryTestSuite`? ########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/TryCast.scala ########## @@ -0,0 +1,88 @@ +/* + * 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.internal.SQLConf +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 `spark.sql.ansi.enabled` as true, " + Review comment: In the first statement, how about explicitly saying that this behaviour follow the ANSI rule? ########## File path: sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala ########## @@ -4118,6 +4118,26 @@ class SQLQuerySuite extends QueryTest with SharedSparkSession with AdaptiveSpark } } + test("try_cast") { + Seq("true", "false").foreach { ansiEnabled => + withSQLConf(SQLConf.ANSI_ENABLED.key -> ansiEnabled) { Review comment: It looks this expr itself does not depend on the ansi option, but we need tests for ansi=true? -- 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. 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