sqlparser/dialect/
postgresql.rs

1// Licensed to the Apache Software Foundation (ASF) under one
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5// to you under the Apache License, Version 2.0 (the
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14// KIND, either express or implied.  See the License for the
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16// under the License.
17
18// Licensed under the Apache License, Version 2.0 (the "License");
19// you may not use this file except in compliance with the License.
20// You may obtain a copy of the License at
21//
22// http://www.apache.org/licenses/LICENSE-2.0
23//
24// Unless required by applicable law or agreed to in writing, software
25// distributed under the License is distributed on an "AS IS" BASIS,
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27// See the License for the specific language governing permissions and
28// limitations under the License.
29use log::debug;
30
31use crate::dialect::{Dialect, Precedence};
32use crate::keywords::Keyword;
33use crate::parser::{Parser, ParserError};
34use crate::tokenizer::Token;
35
36use super::keywords::{self, RESERVED_FOR_IDENTIFIER};
37
38/// Keywords in [`keywords::RESERVED_FOR_TABLE_ALIAS`] because of other dialects, yet are safe for aliasing in PostgreSQL.
39/// See <https://www.postgresql.org/docs/current/sql-keywords-appendix.html>.
40const RESERVED_EXCLUSIONS_FOR_TABLE_ALIAS: &[Keyword] = &[
41    Keyword::CLUSTER,
42    Keyword::DISTRIBUTE,
43    Keyword::EXPLAIN,
44    Keyword::MINUS,
45    Keyword::SAMPLE,
46    Keyword::SORT,
47    Keyword::START,
48    Keyword::TOP,
49    Keyword::VIEW,
50];
51
52/// A [`Dialect`] for [PostgreSQL](https://www.postgresql.org/)
53#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
54#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
55pub struct PostgreSqlDialect {}
56
57const PERIOD_PREC: u8 = 200;
58const DOUBLE_COLON_PREC: u8 = 140;
59const BRACKET_PREC: u8 = 130;
60const COLLATE_PREC: u8 = 120;
61const AT_TZ_PREC: u8 = 110;
62const CARET_PREC: u8 = 100;
63const MUL_DIV_MOD_OP_PREC: u8 = 90;
64const PLUS_MINUS_PREC: u8 = 80;
65// there's no XOR operator in PostgreSQL, but support it here to avoid breaking tests
66const XOR_PREC: u8 = 75;
67const PG_OTHER_PREC: u8 = 70;
68const BETWEEN_LIKE_PREC: u8 = 60;
69const EQ_PREC: u8 = 50;
70const IS_PREC: u8 = 40;
71const NOT_PREC: u8 = 30;
72const AND_PREC: u8 = 20;
73const OR_PREC: u8 = 10;
74
75impl Dialect for PostgreSqlDialect {
76    fn identifier_quote_style(&self, _identifier: &str) -> Option<char> {
77        Some('"')
78    }
79
80    fn is_delimited_identifier_start(&self, ch: char) -> bool {
81        ch == '"' // Postgres does not support backticks to quote identifiers
82    }
83
84    fn is_identifier_start(&self, ch: char) -> bool {
85        ch.is_alphabetic() || ch == '_' ||
86        // PostgreSQL implements Unicode characters in identifiers.
87        !ch.is_ascii()
88    }
89
90    fn is_identifier_part(&self, ch: char) -> bool {
91        ch.is_alphabetic() || ch.is_ascii_digit() || ch == '$' || ch == '_'  ||
92        // PostgreSQL implements Unicode characters in identifiers.
93        !ch.is_ascii()
94    }
95
96    fn supports_unicode_string_literal(&self) -> bool {
97        true
98    }
99
100    fn is_reserved_for_identifier(&self, kw: Keyword) -> bool {
101        if matches!(kw, Keyword::INTERVAL) {
102            false
103        } else {
104            RESERVED_FOR_IDENTIFIER.contains(&kw)
105        }
106    }
107
108    fn is_table_alias(&self, kw: &Keyword, _parser: &mut Parser) -> bool {
109        !keywords::RESERVED_FOR_TABLE_ALIAS.contains(kw)
110            || RESERVED_EXCLUSIONS_FOR_TABLE_ALIAS.contains(kw)
111    }
112
113    /// See <https://www.postgresql.org/docs/current/sql-createoperator.html>
114    fn is_custom_operator_part(&self, ch: char) -> bool {
115        matches!(
116            ch,
117            '+' | '-'
118                | '*'
119                | '/'
120                | '<'
121                | '>'
122                | '='
123                | '~'
124                | '!'
125                | '@'
126                | '#'
127                | '%'
128                | '^'
129                | '&'
130                | '|'
131                | '`'
132                | '?'
133        )
134    }
135
136    fn get_next_precedence(&self, parser: &Parser) -> Option<Result<u8, ParserError>> {
137        let token = parser.peek_token_ref();
138        debug!("get_next_precedence() {token:?}");
139
140        // we only return some custom value here when the behaviour (not merely the numeric value) differs
141        // from the default implementation
142        match &token.token {
143            Token::Word(w)
144                if w.keyword == Keyword::COLLATE && !parser.in_column_definition_state() =>
145            {
146                Some(Ok(COLLATE_PREC))
147            }
148            Token::LBracket => Some(Ok(BRACKET_PREC)),
149            Token::Arrow
150            | Token::LongArrow
151            | Token::HashArrow
152            | Token::HashLongArrow
153            | Token::AtArrow
154            | Token::ArrowAt
155            | Token::HashMinus
156            | Token::AtQuestion
157            | Token::AtAt
158            | Token::Question
159            | Token::QuestionAnd
160            | Token::QuestionPipe
161            | Token::ExclamationMark
162            | Token::Overlap
163            | Token::CaretAt
164            | Token::StringConcat
165            | Token::Sharp
166            | Token::ShiftRight
167            | Token::ShiftLeft
168            | Token::CustomBinaryOperator(_) => Some(Ok(PG_OTHER_PREC)),
169            // lowest prec to prevent it from turning into a binary op
170            Token::Colon => Some(Ok(self.prec_unknown())),
171            _ => None,
172        }
173    }
174
175    fn supports_filter_during_aggregation(&self) -> bool {
176        true
177    }
178
179    fn supports_group_by_expr(&self) -> bool {
180        true
181    }
182
183    fn supports_alter_user_as_alter_role(&self) -> bool {
184        true
185    }
186
187    fn prec_value(&self, prec: Precedence) -> u8 {
188        match prec {
189            Precedence::Period => PERIOD_PREC,
190            Precedence::DoubleColon => DOUBLE_COLON_PREC,
191            Precedence::AtTz => AT_TZ_PREC,
192            Precedence::MulDivModOp => MUL_DIV_MOD_OP_PREC,
193            Precedence::PlusMinus => PLUS_MINUS_PREC,
194            Precedence::Xor => XOR_PREC,
195            Precedence::Ampersand => PG_OTHER_PREC,
196            Precedence::Caret => CARET_PREC,
197            Precedence::Pipe => PG_OTHER_PREC,
198            Precedence::Colon => PG_OTHER_PREC,
199            Precedence::Between => BETWEEN_LIKE_PREC,
200            Precedence::Eq => EQ_PREC,
201            Precedence::Like => BETWEEN_LIKE_PREC,
202            Precedence::Is => IS_PREC,
203            Precedence::PgOther => PG_OTHER_PREC,
204            Precedence::UnaryNot => NOT_PREC,
205            Precedence::And => AND_PREC,
206            Precedence::Or => OR_PREC,
207        }
208    }
209
210    fn allow_extract_custom(&self) -> bool {
211        true
212    }
213
214    fn allow_extract_single_quotes(&self) -> bool {
215        true
216    }
217
218    fn supports_create_index_with_clause(&self) -> bool {
219        true
220    }
221
222    /// see <https://www.postgresql.org/docs/current/sql-explain.html>
223    fn supports_explain_with_utility_options(&self) -> bool {
224        true
225    }
226
227    /// see <https://www.postgresql.org/docs/current/sql-listen.html>
228    /// see <https://www.postgresql.org/docs/current/sql-unlisten.html>
229    /// see <https://www.postgresql.org/docs/current/sql-notify.html>
230    fn supports_listen_notify(&self) -> bool {
231        true
232    }
233
234    /// see <https://www.postgresql.org/docs/current/sql-createtable.html#SQL-CREATETABLE-EXCLUDE>
235    fn supports_exclude_constraint(&self) -> bool {
236        true
237    }
238
239    /// see <https://www.postgresql.org/docs/13/functions-math.html>
240    fn supports_factorial_operator(&self) -> bool {
241        true
242    }
243
244    fn supports_bitwise_shift_operators(&self) -> bool {
245        true
246    }
247
248    /// see <https://www.postgresql.org/docs/current/sql-comment.html>
249    fn supports_comment_on(&self) -> bool {
250        true
251    }
252
253    /// See <https://www.postgresql.org/docs/current/sql-load.html>
254    fn supports_load_extension(&self) -> bool {
255        true
256    }
257
258    /// See <https://www.postgresql.org/docs/current/functions-json.html>
259    ///
260    /// Required to support the colon in:
261    /// ```sql
262    /// SELECT json_object('a': 'b')
263    /// ```
264    fn supports_named_fn_args_with_colon_operator(&self) -> bool {
265        true
266    }
267
268    /// See <https://www.postgresql.org/docs/current/functions-json.html>
269    ///
270    /// Required to support the label in:
271    /// ```sql
272    /// SELECT json_object('label': 'value')
273    /// ```
274    fn supports_named_fn_args_with_expr_name(&self) -> bool {
275        true
276    }
277
278    /// Return true if the dialect supports empty projections in SELECT statements
279    ///
280    /// Example
281    /// ```sql
282    /// SELECT from table_name
283    /// ```
284    fn supports_empty_projections(&self) -> bool {
285        true
286    }
287
288    fn supports_nested_comments(&self) -> bool {
289        true
290    }
291
292    fn supports_string_escape_constant(&self) -> bool {
293        true
294    }
295
296    fn supports_numeric_literal_underscores(&self) -> bool {
297        true
298    }
299
300    /// See: <https://www.postgresql.org/docs/current/arrays.html#ARRAYS-DECLARATION>
301    fn supports_array_typedef_with_brackets(&self) -> bool {
302        true
303    }
304
305    fn supports_geometric_types(&self) -> bool {
306        true
307    }
308
309    fn supports_order_by_using_operator(&self) -> bool {
310        true
311    }
312
313    fn supports_set_names(&self) -> bool {
314        true
315    }
316
317    fn supports_alter_column_type_using(&self) -> bool {
318        true
319    }
320
321    /// PostgreSQL supports right-deep join chains: `t0 JOIN t1 JOIN t2 ON c1 ON c2`
322    /// See: <https://www.postgresql.org/docs/current/queries-table-expressions.html#QUERIES-JOIN>
323    fn supports_left_associative_joins_without_parens(&self) -> bool {
324        false
325    }
326
327    /// Postgres supports `NOTNULL` as an alias for `IS NOT NULL`
328    /// See: <https://www.postgresql.org/docs/17/functions-comparison.html>
329    fn supports_notnull_operator(&self) -> bool {
330        true
331    }
332
333    /// [Postgres] supports optional field and precision options for `INTERVAL` data type.
334    ///
335    /// [Postgres]: https://www.postgresql.org/docs/17/datatype-datetime.html
336    fn supports_interval_options(&self) -> bool {
337        true
338    }
339
340    fn supports_insert_table_alias(&self) -> bool {
341        true
342    }
343
344    fn supports_create_table_like_parenthesized(&self) -> bool {
345        true
346    }
347
348    fn supports_select_wildcard_with_alias(&self) -> bool {
349        true
350    }
351
352    fn supports_comma_separated_trim(&self) -> bool {
353        true
354    }
355
356    fn supports_xml_expressions(&self) -> bool {
357        true
358    }
359
360    fn supports_aliased_function_args(&self) -> bool {
361        true
362    }
363
364    /// Postgres supports query optimizer hints via the `pg_hint_plan` extension,
365    /// using the same comment-prefixed-with-`+` syntax as MySQL and Oracle.
366    ///
367    /// See <https://github.com/ossc-db/pg_hint_plan>
368    fn supports_comment_optimizer_hint(&self) -> bool {
369        true
370    }
371}
sqlparser/dialect/postgresql.rs

sqlparser/dialect/
postgresql.rs
