fix: allow group by same expr in Aggregate

datafusion/common/src/dfschema.rs

@@ -68,14 +68,7 @@ impl DFSchema {
 
         for field in &fields {
             if let Some(qualifier) = field.qualifier() {
-                if !qualified_names.insert((qualifier, field.name())) {
-                    return Err(DataFusionError::SchemaError(
-                        SchemaError::DuplicateQualifiedField {
-                            qualifier: Box::new(qualifier.clone()),
-                            name: field.name().to_string(),
-                        },
-                    ));
-                }
+                qualified_names.insert((qualifier, field.name()));
             } else if !unqualified_names.insert(field.name()) {
                 return Err(DataFusionError::SchemaError(
                     SchemaError::DuplicateUnqualifiedField {
@@ -859,10 +852,7 @@ mod tests {
         let left = DFSchema::try_from_qualified_schema("t1", &test_schema_1())?;
         let right = DFSchema::try_from_qualified_schema("t1", &test_schema_1())?;
         let join = left.join(&right);
-        assert_eq!(
-            join.unwrap_err().to_string(),
-            "Schema error: Schema contains duplicate qualified field name t1.c0",
-        );
+        assert!(join.err().is_none());
         Ok(())
     }
 

datafusion/core/tests/sqllogictests/test_files/aggregate.slt

@@ -41,7 +41,7 @@ LOCATION '../../testing/data/csv/aggregate_test_100.csv'
 #######
 
 # https://github.com/apache/arrow-datafusion/issues/3353
-statement error Aggregations require unique expression names
+statement error DataFusion error: Schema error: Schema contains duplicate unqualified field name "APPROXDISTINCT\(aggregate_test_100\.c9\)"
 SELECT approx_distinct(c9) count_c9, approx_distinct(cast(c9 as varchar)) count_c9_str FROM aggregate_test_100
 
 # csv_query_approx_percentile_cont_with_weight

datafusion/core/tests/sqllogictests/test_files/groupby.slt

@@ -0,0 +1,60 @@
+# 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.
+
+
+statement ok
+CREATE TABLE tab0(col0 INTEGER, col1 INTEGER, col2 INTEGER)
+
+statement ok
+CREATE TABLE tab1(col0 INTEGER, col1 INTEGER, col2 INTEGER)
+
+statement ok
+CREATE TABLE tab2(col0 INTEGER, col1 INTEGER, col2 INTEGER)
+
+statement ok
+INSERT INTO tab0 VALUES(83,0,38)
+
+statement ok
+INSERT INTO tab0 VALUES(26,0,79)
+
+statement ok
+INSERT INTO tab0 VALUES(43,81,24)
+
+statement ok
+INSERT INTO tab1 VALUES(22,6,8)
+
+statement ok
+INSERT INTO tab1 VALUES(28,57,45)
+
+statement ok
+INSERT INTO tab1 VALUES(82,44,71)
+
+statement ok
+INSERT INTO tab2 VALUES(15,61,87)
+
+statement ok
+INSERT INTO tab2 VALUES(91,59,79)
+
+statement ok
+INSERT INTO tab2 VALUES(92,41,58)
+
+# group by same column
+query I
+SELECT 38 FROM tab0 AS cor0 GROUP BY cor0.col1, cor0.col1;
+----
+38
+38

datafusion/expr/src/logical_plan/plan.rs

@@ -16,7 +16,6 @@
 // under the License.
 
 ///! Logical plan types
-use crate::logical_plan::builder::validate_unique_names;
 use crate::logical_plan::display::{GraphvizVisitor, IndentVisitor};
 use crate::logical_plan::extension::UserDefinedLogicalNode;
 use crate::logical_plan::statement::{DmlStatement, Statement};
@@ -1669,7 +1668,6 @@ impl Aggregate {
         let group_expr = enumerate_grouping_sets(group_expr)?;
         let grouping_expr: Vec<Expr> = grouping_set_to_exprlist(group_expr.as_slice())?;
         let all_expr = grouping_expr.iter().chain(aggr_expr.iter());
-        validate_unique_names("Aggregations", all_expr.clone())?;
         let schema = DFSchema::new_with_metadata(
             exprlist_to_fields(all_expr, &input)?,
             input.schema().metadata().clone(),

datafusion/optimizer/src/eliminate_duplicated_expr.rs

@@ -20,7 +20,7 @@ use crate::{OptimizerConfig, OptimizerRule};
 use datafusion_common::Result;
 use datafusion_expr::expr::Sort as ExprSort;
 use datafusion_expr::logical_plan::LogicalPlan;
-use datafusion_expr::{Expr, Sort};
+use datafusion_expr::{Aggregate, Expr, Sort};
 use hashbrown::HashSet;
 
 /// Optimization rule that eliminate duplicated expr.
@@ -74,6 +74,26 @@ impl OptimizerRule for EliminateDuplicatedExpr {
                     })))
                 }
             }
+            LogicalPlan::Aggregate(agg) => {
+                // dedup agg.groupby and keep order
+                let mut dedup_expr = Vec::new();
+                let mut dedup_set = HashSet::new();
+                agg.group_expr.iter().for_each(|expr| {
+                    if !dedup_set.contains(expr) {
+                        dedup_expr.push(expr.clone());
+                        dedup_set.insert(expr);
+                    }
+                });
+                if dedup_expr.len() == agg.group_expr.len() {
+                    Ok(None)
+                } else {
+                    Ok(Some(LogicalPlan::Aggregate(Aggregate::try_new(
+                        agg.input.clone(),
+                        dedup_expr,
+                        agg.aggr_expr.clone(),
+                    )?)))
+                }
+            }
             _ => Ok(None),
         }
     }