sqlparser/dialect/
bigquery.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use crate::ast::Statement;
19use crate::dialect::Dialect;
20use crate::keywords::Keyword;
21use crate::parser::{Parser, ParserError};
22
23/// These keywords are disallowed as column identifiers. Such that
24/// `SELECT 5 AS <col> FROM T` is rejected by BigQuery.
25const RESERVED_FOR_COLUMN_ALIAS: &[Keyword] = &[
26    Keyword::WITH,
27    Keyword::SELECT,
28    Keyword::WHERE,
29    Keyword::GROUP,
30    Keyword::HAVING,
31    Keyword::ORDER,
32    Keyword::LATERAL,
33    Keyword::LIMIT,
34    Keyword::FETCH,
35    Keyword::UNION,
36    Keyword::EXCEPT,
37    Keyword::INTERSECT,
38    Keyword::FROM,
39    Keyword::INTO,
40    Keyword::END,
41];
42
43/// A [`Dialect`] for [Google Bigquery](https://cloud.google.com/bigquery/)
44#[derive(Debug, Default)]
45pub struct BigQueryDialect;
46
47impl Dialect for BigQueryDialect {
48    fn parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
49        self.maybe_parse_statement(parser)
50    }
51
52    /// See <https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#identifiers>
53    fn is_delimited_identifier_start(&self, ch: char) -> bool {
54        ch == '`'
55    }
56
57    fn supports_projection_trailing_commas(&self) -> bool {
58        true
59    }
60
61    /// See <https://cloud.google.com/bigquery/docs/reference/standard-sql/data-definition-language#create_table_statement>
62    fn supports_column_definition_trailing_commas(&self) -> bool {
63        true
64    }
65
66    fn is_identifier_start(&self, ch: char) -> bool {
67        ch.is_ascii_lowercase() || ch.is_ascii_uppercase() || ch == '_'
68            // BigQuery supports `@@foo.bar` variable syntax in its procedural language.
69            // https://cloud.google.com/bigquery/docs/reference/standard-sql/procedural-language#beginexceptionend
70            || ch == '@'
71    }
72
73    fn is_identifier_part(&self, ch: char) -> bool {
74        ch.is_ascii_lowercase() || ch.is_ascii_uppercase() || ch.is_ascii_digit() || ch == '_'
75    }
76
77    /// See [doc](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_literals)
78    fn supports_triple_quoted_string(&self) -> bool {
79        true
80    }
81
82    /// See [doc](https://cloud.google.com/bigquery/docs/reference/standard-sql/navigation_functions#first_value)
83    fn supports_window_function_null_treatment_arg(&self) -> bool {
84        true
85    }
86
87    // See https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#escape_sequences
88    fn supports_string_literal_backslash_escape(&self) -> bool {
89        true
90    }
91
92    /// See [doc](https://cloud.google.com/bigquery/docs/reference/standard-sql/window-function-calls#ref_named_window)
93    fn supports_window_clause_named_window_reference(&self) -> bool {
94        true
95    }
96
97    /// See [doc](https://cloud.google.com/bigquery/docs/reference/standard-sql/procedural-language#set)
98    fn supports_parenthesized_set_variables(&self) -> bool {
99        true
100    }
101
102    // See https://cloud.google.com/bigquery/docs/reference/standard-sql/query-syntax#select_except
103    fn supports_select_wildcard_except(&self) -> bool {
104        true
105    }
106
107    fn require_interval_qualifier(&self) -> bool {
108        true
109    }
110
111    // See https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#constructing_a_struct
112    fn supports_struct_literal(&self) -> bool {
113        true
114    }
115
116    /// See <https://cloud.google.com/bigquery/docs/reference/standard-sql/query-syntax#select_expression_star>
117    fn supports_select_expr_star(&self) -> bool {
118        true
119    }
120
121    /// See <https://cloud.google.com/bigquery/docs/reference/standard-sql/procedural-language#execute_immediate>
122    fn supports_execute_immediate(&self) -> bool {
123        true
124    }
125
126    // See <https://cloud.google.com/bigquery/docs/access-historical-data>
127    fn supports_timestamp_versioning(&self) -> bool {
128        true
129    }
130
131    // See <https://cloud.google.com/bigquery/docs/reference/standard-sql/query-syntax#group_by_clause>
132    fn supports_group_by_expr(&self) -> bool {
133        true
134    }
135
136    fn is_column_alias(&self, kw: &Keyword, _parser: &mut Parser) -> bool {
137        !RESERVED_FOR_COLUMN_ALIAS.contains(kw)
138    }
139
140    fn supports_pipe_operator(&self) -> bool {
141        true
142    }
143}
144
145impl BigQueryDialect {
146    fn maybe_parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
147        if parser.peek_keyword(Keyword::BEGIN) {
148            return Some(self.parse_begin(parser));
149        }
150        None
151    }
152
153    /// Parse a `BEGIN` statement.
154    /// <https://cloud.google.com/bigquery/docs/reference/standard-sql/procedural-language#beginexceptionend>
155    fn parse_begin(&self, parser: &mut Parser) -> Result<Statement, ParserError> {
156        parser.expect_keyword(Keyword::BEGIN)?;
157
158        let statements = parser.parse_statement_list(&[Keyword::EXCEPTION, Keyword::END])?;
159
160        let has_exception_when_clause = parser.parse_keywords(&[
161            Keyword::EXCEPTION,
162            Keyword::WHEN,
163            Keyword::ERROR,
164            Keyword::THEN,
165        ]);
166        let exception_statements = if has_exception_when_clause {
167            if !parser.peek_keyword(Keyword::END) {
168                Some(parser.parse_statement_list(&[Keyword::END])?)
169            } else {
170                Some(Default::default())
171            }
172        } else {
173            None
174        };
175
176        parser.expect_keyword(Keyword::END)?;
177
178        Ok(Statement::StartTransaction {
179            begin: true,
180            statements,
181            exception_statements,
182            has_end_keyword: true,
183            transaction: None,
184            modifier: None,
185            modes: Default::default(),
186        })
187    }
188}
sqlparser/dialect/bigquery.rs

sqlparser/dialect/
bigquery.rs
