Jimexist commented on a change in pull request #492: URL: https://github.com/apache/arrow-datafusion/pull/492#discussion_r645944824
########## File path: datafusion/src/physical_plan/window_frames.rs ########## @@ -0,0 +1,200 @@ +// 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. + +//! Window frame +//! +//! The frame-spec determines which output rows are read by an aggregate window function. The frame-spec consists of four parts: +//! - A frame type - either ROWS, RANGE or GROUPS, +//! - A starting frame boundary, +//! - An ending frame boundary, +//! - An EXCLUDE clause. + +use crate::error::{DataFusionError, Result}; +use sqlparser::ast::{WindowFrame, WindowFrameBound, WindowFrameUnits}; + +const DEFAULT_WINDOW_FRAME: WindowFrame = WindowFrame { + units: WindowFrameUnits::Range, + start_bound: WindowFrameBound::Preceding(None), + end_bound: Some(WindowFrameBound::CurrentRow), +}; + +fn get_bound_rank(bound: &WindowFrameBound) -> (u8, u64) { + match bound { + WindowFrameBound::Preceding(None) => (0, 0), + WindowFrameBound::Following(None) => (4, 0), + WindowFrameBound::Preceding(Some(0)) + | WindowFrameBound::CurrentRow + | WindowFrameBound::Following(Some(0)) => (2, 0), + WindowFrameBound::Preceding(Some(v)) => (1, u64::MAX - *v), + WindowFrameBound::Following(Some(v)) => (3, *v), + } +} + +/// Validate a window frame if present, otherwise return the default window frame. +pub(crate) fn validate_window_frame( Review comment: see https://github.com/apache/arrow-datafusion/pull/506 -- 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: [email protected]
