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Parse SUBSTRING FROM syntax in all dialects, reflect change in the AST (#1173)

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Ophir LOJKINE 2024-03-13 16:08:27 +01:00 • committed by GitHub
parent 929c646bba
commit 6b03a259aa
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7 changed files with 47 additions and 95 deletions
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9
src/ast/mod.rs
View file

@ -559,13 +559,18 @@ pub enum Expr {
/// ```sql
/// SUBSTRING(<expr> [FROM <expr>] [FOR <expr>])
/// ```
/// or
/// ```sql
/// SUBSTRING(<expr>, <expr>, <expr>)
/// ```
Substring {
expr: Box<Expr>,
substring_from: Option<Box<Expr>>,
substring_for: Option<Box<Expr>>,
// Some dialects use `SUBSTRING(expr [FROM start] [FOR len])` syntax while others omit FROM,
// FOR keywords (e.g. Microsoft SQL Server). This flags is used for formatting.
/// false if the expression is represented using the `SUBSTRING(expr [FROM start] [FOR len])` syntax
/// true if the expression is represented using the `SUBSTRING(expr, start, len)` syntax
/// This flag is used for formatting.
special: bool,
},
/// ```sql

8
src/dialect/mod.rs
View file

@ -135,10 +135,6 @@ pub trait Dialect: Debug + Any {
fn supports_group_by_expr(&self) -> bool {
false
}
/// Returns true if the dialect supports `SUBSTRING(expr [FROM start] [FOR len])` expressions
fn supports_substring_from_for_expr(&self) -> bool {
true
}
/// Returns true if the dialect supports `(NOT) IN ()` expressions
fn supports_in_empty_list(&self) -> bool {
false
@ -325,10 +321,6 @@ mod tests {
self.0.supports_group_by_expr()
}
fn supports_substring_from_for_expr(&self) -> bool {
self.0.supports_substring_from_for_expr()
}
fn supports_in_empty_list(&self) -> bool {
self.0.supports_in_empty_list()
}

4
src/dialect/mssql.rs
View file

@ -40,8 +40,4 @@ impl Dialect for MsSqlDialect {
fn convert_type_before_value(&self) -> bool {
true
}
fn supports_substring_from_for_expr(&self) -> bool {
false
}
}

60
src/parser/mod.rs
View file

@ -1525,47 +1525,27 @@ impl<'a> Parser<'a> {
}
pub fn parse_substring_expr(&mut self) -> Result<Expr, ParserError> {
if self.dialect.supports_substring_from_for_expr() {
// PARSE SUBSTRING (EXPR [FROM 1] [FOR 3])
self.expect_token(&Token::LParen)?;
let expr = self.parse_expr()?;
let mut from_expr = None;
if self.parse_keyword(Keyword::FROM) || self.consume_token(&Token::Comma) {
from_expr = Some(self.parse_expr()?);
}
let mut to_expr = None;
if self.parse_keyword(Keyword::FOR) || self.consume_token(&Token::Comma) {
to_expr = Some(self.parse_expr()?);
}
self.expect_token(&Token::RParen)?;
Ok(Expr::Substring {
expr: Box::new(expr),
substring_from: from_expr.map(Box::new),
substring_for: to_expr.map(Box::new),
special: false,
})
} else {
// PARSE SUBSTRING(EXPR, start, length)
self.expect_token(&Token::LParen)?;
let expr = self.parse_expr()?;
self.expect_token(&Token::Comma)?;
let from_expr = Some(self.parse_expr()?);
self.expect_token(&Token::Comma)?;
let to_expr = Some(self.parse_expr()?);
self.expect_token(&Token::RParen)?;
Ok(Expr::Substring {
expr: Box::new(expr),
substring_from: from_expr.map(Box::new),
substring_for: to_expr.map(Box::new),
special: true,
})
// PARSE SUBSTRING (EXPR [FROM 1] [FOR 3])
self.expect_token(&Token::LParen)?;
let expr = self.parse_expr()?;
let mut from_expr = None;
let special = self.consume_token(&Token::Comma);
if special || self.parse_keyword(Keyword::FROM) {
from_expr = Some(self.parse_expr()?);
}
let mut to_expr = None;
if self.parse_keyword(Keyword::FOR) || self.consume_token(&Token::Comma) {
to_expr = Some(self.parse_expr()?);
}
self.expect_token(&Token::RParen)?;
Ok(Expr::Substring {
expr: Box::new(expr),
substring_from: from_expr.map(Box::new),
substring_for: to_expr.map(Box::new),
special,
})
}
pub fn parse_overlay_expr(&mut self) -> Result<Expr, ParserError> {