refactor: move aggregate_statistics to datafusion-physical-optimizer

datafusion/common/src/utils/expr.rs

@@ -0,0 +1,24 @@
+// 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.
+
+//! Expression utilities
+
+use crate::ScalarValue;
+
+///  The value to which `COUNT(*)` is expanded to in
+///  `COUNT(<constant>)` expressions
+pub const COUNT_STAR_EXPANSION: ScalarValue = ScalarValue::Int64(Some(1));

datafusion/common/src/utils/mod.rs

@@ -17,6 +17,7 @@
 
 //! This module provides the bisect function, which implements binary search.
 
+pub mod expr;
 pub mod memory;
 pub mod proxy;