gengliangwang commented on code in PR #39508: URL: https://github.com/apache/spark/pull/39508#discussion_r1081742355
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveReferencesInAggregate.scala: ########## @@ -0,0 +1,205 @@ +/* + * 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.analysis + +import org.apache.spark.sql.catalyst.SQLConfHelper +import org.apache.spark.sql.catalyst.expressions.{Alias, Attribute, Expression, GetStructField, NamedExpression} +import org.apache.spark.sql.catalyst.expressions.aggregate.AggregateExpression +import org.apache.spark.sql.catalyst.plans.logical.{Aggregate, AppendColumns, LogicalPlan} +import org.apache.spark.sql.catalyst.trees.TreePattern.{LATERAL_COLUMN_ALIAS_REFERENCE, UNRESOLVED_ATTRIBUTE} + +/** + * A virtual rule to resolve [[UnresolvedAttribute]] in [[Aggregate]]. It's only used by the real + * rule `ResolveReferences`. The column resolution order for [[Aggregate]] is: + * 1. Resolves the column to [[AttributeReference]] with the output of the child plan. This + * includes metadata columns as well. + * 2. Resolves the column to a literal function which is allowed to be invoked without braces, e.g. + * `SELECT col, current_date FROM t`. + * 3. If `Aggregate.aggregateExpressions` are all resolved, resolve GROUP BY alias and GROUP BY ALL + * for `Aggregate.groupingExpressions`: + * 3.1. If the grouping expressions contain an unresolved column whose name matches an alias in the + * SELECT list, resolves that unresolved column to the alias. This is to support SQL pattern + * like `SELECT a + b AS c, max(col) FROM t GROUP BY c`. + * 3.2. If the grouping expressions only have one single unresolved column named 'ALL', expanded it + * to include all non-aggregate columns in the SELECT list. This is to support SQL pattern like + * `SELECT col1, col2, agg_expr(...) FROM t GROUP BY ALL`. + * 4. Resolves the column in `Aggregate.aggregateExpressions` to [[LateralColumnAliasReference]] if Review Comment: nit: column => columns -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
