sqlparser/dialect/
mssql.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::helpers::attached_token::AttachedToken;
19use crate::ast::{
20    BeginEndStatements, ConditionalStatementBlock, ConditionalStatements, CreateTrigger,
21    GranteesType, IfStatement, Statement,
22};
23use crate::dialect::Dialect;
24use crate::keywords::Keyword;
25use crate::parser::{Parser, ParserError};
26use crate::tokenizer::Token;
27#[cfg(not(feature = "std"))]
28use alloc::{vec, vec::Vec};
29
30/// A [`Dialect`] for [Microsoft SQL Server](https://www.microsoft.com/en-us/sql-server/)
31#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
32#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
33pub struct MsSqlDialect {}
34
35impl Dialect for MsSqlDialect {
36    fn is_delimited_identifier_start(&self, ch: char) -> bool {
37        ch == '"' || ch == '['
38    }
39
40    fn is_identifier_start(&self, ch: char) -> bool {
41        // See https://docs.microsoft.com/en-us/sql/relational-databases/databases/database-identifiers?view=sql-server-2017#rules-for-regular-identifiers
42        ch.is_alphabetic() || ch == '_' || ch == '#' || ch == '@'
43    }
44
45    fn is_identifier_part(&self, ch: char) -> bool {
46        ch.is_alphabetic()
47            || ch.is_ascii_digit()
48            || ch == '@'
49            || ch == '$'
50            || ch == '#'
51            || ch == '_'
52    }
53
54    fn identifier_quote_style(&self, _identifier: &str) -> Option<char> {
55        Some('[')
56    }
57
58    /// SQL Server has `CONVERT(type, value)` instead of `CONVERT(value, type)`
59    /// <https://learn.microsoft.com/en-us/sql/t-sql/functions/cast-and-convert-transact-sql?view=sql-server-ver16>
60    fn convert_type_before_value(&self) -> bool {
61        true
62    }
63
64    fn supports_outer_join_operator(&self) -> bool {
65        true
66    }
67
68    /// SQL Server supports `$` as a prefix for money literals
69    /// <https://learn.microsoft.com/en-us/sql/t-sql/data-types/constants-transact-sql?view=sql-server-ver17#money-constants>
70    fn supports_dollar_as_money_prefix(&self) -> bool {
71        true
72    }
73
74    fn supports_connect_by(&self) -> bool {
75        true
76    }
77
78    fn supports_eq_alias_assignment(&self) -> bool {
79        true
80    }
81
82    fn supports_try_convert(&self) -> bool {
83        true
84    }
85
86    /// In MSSQL, there is no boolean type, and `true` and `false` are valid column names
87    fn supports_boolean_literals(&self) -> bool {
88        false
89    }
90
91    fn supports_named_fn_args_with_colon_operator(&self) -> bool {
92        true
93    }
94
95    fn supports_named_fn_args_with_expr_name(&self) -> bool {
96        true
97    }
98
99    fn supports_named_fn_args_with_rarrow_operator(&self) -> bool {
100        false
101    }
102
103    fn supports_start_transaction_modifier(&self) -> bool {
104        true
105    }
106
107    fn supports_end_transaction_modifier(&self) -> bool {
108        true
109    }
110
111    /// See: <https://learn.microsoft.com/en-us/sql/t-sql/statements/set-statements-transact-sql>
112    fn supports_set_stmt_without_operator(&self) -> bool {
113        true
114    }
115
116    /// See: <https://learn.microsoft.com/en-us/sql/relational-databases/tables/querying-data-in-a-system-versioned-temporal-table>
117    fn supports_table_versioning(&self) -> bool {
118        true
119    }
120
121    /// See <https://learn.microsoft.com/en-us/sql/t-sql/language-elements/slash-star-comment-transact-sql?view=sql-server-ver16>
122    fn supports_nested_comments(&self) -> bool {
123        true
124    }
125
126    /// See <https://learn.microsoft.com/en-us/sql/t-sql/queries/from-transact-sql>
127    fn supports_object_name_double_dot_notation(&self) -> bool {
128        true
129    }
130
131    /// See <https://learn.microsoft.com/en-us/sql/relational-databases/security/authentication-access/server-level-roles>
132    fn get_reserved_grantees_types(&self) -> &[GranteesType] {
133        &[GranteesType::Public]
134    }
135
136    fn is_select_item_alias(&self, explicit: bool, kw: &Keyword, parser: &mut Parser) -> bool {
137        match kw {
138            // List of keywords that cannot be used as select item (column) aliases in MSSQL
139            // regardless of whether the alias is explicit or implicit.
140            //
141            // These are T-SQL statement-starting keywords; allowing them as implicit aliases
142            // causes the parser to consume the keyword as an alias for the previous expression,
143            // then fail on the token that follows (e.g. `TABLE`, `@var`, `sp_name`, …).
144            Keyword::IF
145            | Keyword::ELSE
146            | Keyword::DECLARE
147            | Keyword::EXEC
148            | Keyword::EXECUTE
149            | Keyword::INSERT
150            | Keyword::UPDATE
151            | Keyword::DELETE
152            | Keyword::DROP
153            | Keyword::CREATE
154            | Keyword::ALTER
155            | Keyword::TRUNCATE
156            | Keyword::PRINT
157            | Keyword::WHILE
158            | Keyword::RETURN
159            | Keyword::THROW
160            | Keyword::RAISERROR
161            | Keyword::MERGE => false,
162            _ => explicit || self.is_column_alias(kw, parser),
163        }
164    }
165
166    fn is_table_factor_alias(&self, explicit: bool, kw: &Keyword, parser: &mut Parser) -> bool {
167        match kw {
168            // List of keywords that cannot be used as table aliases in MSSQL
169            // regardless of whether the alias is explicit or implicit.
170            //
171            // These are T-SQL statement-starting keywords. Without blocking them here,
172            // a bare `SELECT * FROM t` followed by a newline and one of these keywords
173            // would cause the parser to consume the keyword as a table alias for `t`,
174            // then fail on the token that follows (e.g. `@var`, `sp_name`, `TABLE`, …).
175            //
176            // `SET` is already covered by the global `RESERVED_FOR_TABLE_ALIAS` list;
177            // the keywords below are MSSQL-specific additions.
178            Keyword::IF
179            | Keyword::ELSE
180            | Keyword::DECLARE
181            | Keyword::EXEC
182            | Keyword::EXECUTE
183            | Keyword::INSERT
184            | Keyword::UPDATE
185            | Keyword::DELETE
186            | Keyword::DROP
187            | Keyword::CREATE
188            | Keyword::ALTER
189            | Keyword::TRUNCATE
190            | Keyword::PRINT
191            | Keyword::WHILE
192            | Keyword::RETURN
193            | Keyword::THROW
194            | Keyword::RAISERROR
195            | Keyword::MERGE => false,
196            _ => explicit || self.is_table_alias(kw, parser),
197        }
198    }
199
200    fn parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
201        if parser.parse_keyword(Keyword::BEGIN) {
202            // Check if this is a BEGIN...END block rather than BEGIN TRANSACTION
203            let is_block = parser
204                .maybe_parse(|p| {
205                    if p.parse_transaction_modifier().is_some()
206                        || p.parse_one_of_keywords(&[
207                            Keyword::TRANSACTION,
208                            Keyword::WORK,
209                            Keyword::TRAN,
210                        ])
211                        .is_some()
212                        || matches!(p.peek_token_ref().token, Token::SemiColon | Token::EOF)
213                    {
214                        p.expected_ref("statement", p.peek_token_ref())
215                    } else {
216                        Ok(())
217                    }
218                })
219                .unwrap_or(None)
220                .is_some();
221            if is_block {
222                Some(parser.parse_begin_exception_end())
223            } else {
224                parser.prev_token();
225                None
226            }
227        } else if parser.peek_keyword(Keyword::IF) {
228            Some(self.parse_if_stmt(parser))
229        } else if parser.parse_keywords(&[Keyword::CREATE, Keyword::TRIGGER]) {
230            Some(self.parse_create_trigger(parser, false))
231        } else if parser.parse_keywords(&[
232            Keyword::CREATE,
233            Keyword::OR,
234            Keyword::ALTER,
235            Keyword::TRIGGER,
236        ]) {
237            Some(self.parse_create_trigger(parser, true))
238        } else {
239            None
240        }
241    }
242
243    fn get_next_precedence(&self, parser: &Parser) -> Option<Result<u8, ParserError>> {
244        let token = parser.peek_token_ref();
245        match &token.token {
246            // lowest prec to prevent it from turning into a binary op
247            Token::Colon => Some(Ok(self.prec_unknown())),
248            _ => None,
249        }
250    }
251}
252
253impl MsSqlDialect {
254    /// ```sql
255    /// IF boolean_expression
256    ///     { sql_statement | statement_block }
257    /// [ ELSE
258    ///     { sql_statement | statement_block } ]
259    /// ```
260    fn parse_if_stmt(&self, parser: &mut Parser) -> Result<Statement, ParserError> {
261        let if_token = parser.expect_keyword(Keyword::IF)?;
262
263        let condition = parser.parse_expr()?;
264
265        let if_block = if parser.peek_keyword(Keyword::BEGIN) {
266            let begin_token = parser.expect_keyword(Keyword::BEGIN)?;
267            let statements = self.parse_statement_list(parser, Some(Keyword::END))?;
268            let end_token = parser.expect_keyword(Keyword::END)?;
269            ConditionalStatementBlock {
270                start_token: AttachedToken(if_token),
271                condition: Some(condition),
272                then_token: None,
273                conditional_statements: ConditionalStatements::BeginEnd(BeginEndStatements {
274                    begin_token: AttachedToken(begin_token),
275                    statements,
276                    end_token: AttachedToken(end_token),
277                }),
278            }
279        } else {
280            let stmt = parser.parse_statement()?;
281            ConditionalStatementBlock {
282                start_token: AttachedToken(if_token),
283                condition: Some(condition),
284                then_token: None,
285                conditional_statements: ConditionalStatements::Sequence {
286                    statements: vec![stmt],
287                },
288            }
289        };
290
291        let mut prior_statement_ended_with_semi_colon = false;
292        while let Token::SemiColon = parser.peek_token_ref().token {
293            parser.advance_token();
294            prior_statement_ended_with_semi_colon = true;
295        }
296
297        let mut else_block = None;
298        if parser.peek_keyword(Keyword::ELSE) {
299            let else_token = parser.expect_keyword(Keyword::ELSE)?;
300            if parser.peek_keyword(Keyword::BEGIN) {
301                let begin_token = parser.expect_keyword(Keyword::BEGIN)?;
302                let statements = self.parse_statement_list(parser, Some(Keyword::END))?;
303                let end_token = parser.expect_keyword(Keyword::END)?;
304                else_block = Some(ConditionalStatementBlock {
305                    start_token: AttachedToken(else_token),
306                    condition: None,
307                    then_token: None,
308                    conditional_statements: ConditionalStatements::BeginEnd(BeginEndStatements {
309                        begin_token: AttachedToken(begin_token),
310                        statements,
311                        end_token: AttachedToken(end_token),
312                    }),
313                });
314            } else {
315                let stmt = parser.parse_statement()?;
316                else_block = Some(ConditionalStatementBlock {
317                    start_token: AttachedToken(else_token),
318                    condition: None,
319                    then_token: None,
320                    conditional_statements: ConditionalStatements::Sequence {
321                        statements: vec![stmt],
322                    },
323                });
324            }
325        } else if prior_statement_ended_with_semi_colon {
326            parser.prev_token();
327        }
328
329        Ok(IfStatement {
330            if_block,
331            else_block,
332            elseif_blocks: Vec::new(),
333            end_token: None,
334        }
335        .into())
336    }
337
338    /// Parse `CREATE TRIGGER` for [MsSql]
339    ///
340    /// [MsSql]: https://learn.microsoft.com/en-us/sql/t-sql/statements/create-trigger-transact-sql
341    fn parse_create_trigger(
342        &self,
343        parser: &mut Parser,
344        or_alter: bool,
345    ) -> Result<Statement, ParserError> {
346        let name = parser.parse_object_name(false)?;
347        parser.expect_keyword_is(Keyword::ON)?;
348        let table_name = parser.parse_object_name(false)?;
349        let period = parser.parse_trigger_period()?;
350        let events = parser.parse_comma_separated(Parser::parse_trigger_event)?;
351
352        parser.expect_keyword_is(Keyword::AS)?;
353        let statements = Some(parser.parse_conditional_statements(&[Keyword::END])?);
354
355        Ok(CreateTrigger {
356            or_alter,
357            temporary: false,
358            or_replace: false,
359            is_constraint: false,
360            name,
361            period: Some(period),
362            period_before_table: false,
363            events,
364            table_name,
365            referenced_table_name: None,
366            referencing: Vec::new(),
367            trigger_object: None,
368            condition: None,
369            exec_body: None,
370            statements_as: true,
371            statements,
372            characteristics: None,
373        }
374        .into())
375    }
376
377    /// Parse a sequence of statements, optionally separated by semicolon.
378    ///
379    /// Stops parsing when reaching EOF or the given keyword.
380    fn parse_statement_list(
381        &self,
382        parser: &mut Parser,
383        terminal_keyword: Option<Keyword>,
384    ) -> Result<Vec<Statement>, ParserError> {
385        let mut stmts = Vec::new();
386        loop {
387            if let Token::EOF = parser.peek_token_ref().token {
388                break;
389            }
390            if let Some(term) = terminal_keyword {
391                if parser.peek_keyword(term) {
392                    break;
393                }
394            }
395            stmts.push(parser.parse_statement()?);
396            while let Token::SemiColon = parser.peek_token_ref().token {
397                parser.advance_token();
398            }
399        }
400        Ok(stmts)
401    }
402}
sqlparser/dialect/mssql.rs

sqlparser/dialect/
mssql.rs
