Jimexist commented on a change in pull request #1285: URL: https://github.com/apache/arrow-datafusion/pull/1285#discussion_r750909594
########## File path: datafusion-cli/src/functions.rs ########## @@ -0,0 +1,192 @@ +// 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. + +//! Command within CLI +use datafusion::error::{DataFusionError, Result}; +use std::fmt; +use std::str::FromStr; + +#[derive(Debug)] +pub enum Function { + Select, + Explain, + Show, + CreateTable, + CreateTableAs, + Insert, + DropTable, +} + +const ALL_FUNCTIONS: [Function; 7] = [ + Function::CreateTable, + Function::CreateTableAs, + Function::DropTable, + Function::Explain, + Function::Insert, + Function::Select, + Function::Show, +]; + +impl Function { + pub fn function_details(&self) -> Result<()> { + match self { + Function::Select => { + let details = " +Command: SELECT +Description: retrieve rows from a table or view +Syntax: +SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ] + [ * | expression [ [ AS ] output_name ] [, ...] ] + [ FROM from_item [, ...] ] + [ WHERE condition ] + [ GROUP BY [ ALL | DISTINCT ] grouping_element [, ...] ] + [ HAVING condition ] + [ WINDOW window_name AS ( window_definition ) [, ...] ] + [ { UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select ] + [ ORDER BY expression [ ASC | DESC | USING operator ] [ NULLS { FIRST | LAST } ] [, ...] ] + [ LIMIT { count | ALL } ] + [ OFFSET start [ ROW | ROWS ] ] + +where from_item can be one of: + + [ ONLY ] table_name [ * ] [ [ AS ] alias [ ( column_alias [, ...] ) ] ] + [ TABLESAMPLE sampling_method ( argument [, ...] ) [ REPEATABLE ( seed ) ] ] + [ LATERAL ] ( select ) [ AS ] alias [ ( column_alias [, ...] ) ] + with_query_name [ [ AS ] alias [ ( column_alias [, ...] ) ] ] + [ LATERAL ] function_name ( [ argument [, ...] ] ) + [ WITH ORDINALITY ] [ [ AS ] alias [ ( column_alias [, ...] ) ] ] + [ LATERAL ] function_name ( [ argument [, ...] ] ) [ AS ] alias ( column_definition [, ...] ) + [ LATERAL ] function_name ( [ argument [, ...] ] ) AS ( column_definition [, ...] ) + [ LATERAL ] ROWS FROM( function_name ( [ argument [, ...] ] ) [ AS ( column_definition [, ...] ) ] [, ...] ) + [ WITH ORDINALITY ] [ [ AS ] alias [ ( column_alias [, ...] ) ] ] + from_item [ NATURAL ] join_type from_item [ ON join_condition | USING ( join_column [, ...] ) [ AS join_using_alias ] ] + +and grouping_element can be one of: + + ( ) + expression + ( expression [, ...] ) + +and with_query is: + + with_query_name [ ( column_name [, ...] ) ] AS [ [ NOT ] MATERIALIZED ] ( select | values | insert | update | delete ) + +TABLE [ ONLY ] table_name [ * ]"; + println!("{}", details) + } + Function::Explain => { + let details = " +Command: EXPLAIN +Description: show the execution plan of a statement +Syntax: +EXPLAIN [ ANALYZE ] statement +"; + println!("{}", details) + } + Function::Show => { + let details = " +Command: SHOW +Description: show the value of a run-time parameter +Syntax: +SHOW name +"; + println!("{}", details) + } + Function::CreateTable => { + let details = " +Command: CREATE TABLE +Description: define a new table +Syntax: +CREATE [ EXTERNAL ] TABLE table_name ( [ + { column_name data_type } + [, ... ] +] ) +"; + println!("{}", details) + } + Function::CreateTableAs => { + let details = " +Command: CREATE TABLE AS +Description: define a new table from the results of a query +Syntax: +CREATE TABLE table_name + [ (column_name [, ...] ) ] + AS query + [ WITH [ NO ] DATA ] +"; + println!("{}", details) + } + Function::Insert => { + let details = " +Command: INSERT +Description: create new rows in a table +Syntax: +INSERT INTO table_name [ ( column_name [, ...] ) ] + { VALUES ( { expression } [, ...] ) [, ...] } +"; + println!("{}", details) + } + Function::DropTable => { + let details = " +Command: DROP TABLE +Description: remove a table +Syntax: +DROP TABLE [ IF EXISTS ] name [, ...] +"; + println!("{}", details) + } + } + Ok(()) + } +} + +impl FromStr for Function { + type Err = (); + + fn from_str(s: &str) -> std::result::Result<Self, Self::Err> { + Ok(match s.trim().to_uppercase().as_str() { + "SELECT" => Self::Select, + "EXPLAIN" => Self::Explain, + "SHOW" => Self::Show, + "CREATE TABLE" => Self::CreateTable, + "CREATE TABLE AS" => Self::CreateTableAs, + "INSERT" => Self::Insert, + "DROP TABLE" => Self::DropTable, + _ => return Err(()), + }) + } +} + +impl fmt::Display for Function { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + match *self { + Function::Select => write!(f, "SELECT"), + Function::Explain => write!(f, "EXPLAIN"), + Function::Show => write!(f, "SHOW"), + Function::CreateTable => write!(f, "CREATE TABLE"), + Function::CreateTableAs => write!(f, "CREATE TABLE AS"), + Function::Insert => write!(f, "INSERT"), + Function::DropTable => write!(f, "DROP TABLE"), + } + } +} + +pub fn display_all_functions() -> Result<()> { Review comment: how about formatting into a record batch? -- This is an automated message from the Apache Git Service. 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