Add ODBC escape syntax support for time expressions (#1953)

Author: etgarperets

src/ast/mod.rs

@@ -1014,12 +1014,7 @@ pub enum Expr {
     /// A constant of form `<data_type> 'value'`.
     /// This can represent ANSI SQL `DATE`, `TIME`, and `TIMESTAMP` literals (such as `DATE '2020-01-01'`),
     /// as well as constants of other types (a non-standard PostgreSQL extension).
-    TypedString {
-        data_type: DataType,
-        /// The value of the constant.
-        /// Hint: you can unwrap the string value using `value.into_string()`.
-        value: ValueWithSpan,
-    },
+    TypedString(TypedString),
     /// Scalar function call e.g. `LEFT(foo, 5)`
     Function(Function),
     /// `CASE [<operand>] WHEN <condition> THEN <result> ... [ELSE <result>] END`
@@ -1734,10 +1729,7 @@ impl fmt::Display for Expr {
             Expr::Nested(ast) => write!(f, "({ast})"),
             Expr::Value(v) => write!(f, "{v}"),
             Expr::Prefixed { prefix, value } => write!(f, "{prefix} {value}"),
-            Expr::TypedString { data_type, value } => {
-                write!(f, "{data_type}")?;
-                write!(f, " {value}")
-            }
+            Expr::TypedString(ts) => ts.fmt(f),
             Expr::Function(fun) => fun.fmt(f),
             Expr::Case {
                 case_token: _,
@@ -7450,6 +7442,52 @@ pub struct DropDomain {
     pub drop_behavior: Option<DropBehavior>,
 }
 
+/// A constant of form `<data_type> 'value'`.
+/// This can represent ANSI SQL `DATE`, `TIME`, and `TIMESTAMP` literals (such as `DATE '2020-01-01'`),
+/// as well as constants of other types (a non-standard PostgreSQL extension).
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub struct TypedString {
+    pub data_type: DataType,
+    /// The value of the constant.
+    /// Hint: you can unwrap the string value using `value.into_string()`.
+    pub value: ValueWithSpan,
+    /// Flags whether this TypedString uses the [ODBC syntax].
+    ///
+    /// Example:
+    /// ```sql
+    /// -- An ODBC date literal:
+    /// SELECT {d '2025-07-16'}
+    /// -- This is equivalent to the standard ANSI SQL literal:
+    /// SELECT DATE '2025-07-16'
+    ///
+    /// [ODBC syntax]: https://learn.microsoft.com/en-us/sql/odbc/reference/develop-app/date-time-and-timestamp-literals?view=sql-server-2017
+    pub uses_odbc_syntax: bool,
+}
+
+impl fmt::Display for TypedString {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let data_type = &self.data_type;
+        let value = &self.value;
+        match self.uses_odbc_syntax {
+            false => {
+                write!(f, "{data_type}")?;
+                write!(f, " {value}")
+            }
+            true => {
+                let prefix = match data_type {
+                    DataType::Date => "d",
+                    DataType::Time(..) => "t",
+                    DataType::Timestamp(..) => "ts",
+                    _ => "?",
+                };
+                write!(f, "{{{prefix} {value}}}")
+            }
+        }
+    }
+}
+
 /// A function call
 #[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]

src/ast/spans.rs

@@ -15,7 +15,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-use crate::ast::{query::SelectItemQualifiedWildcardKind, ColumnOptions, ExportData};
+use crate::ast::{query::SelectItemQualifiedWildcardKind, ColumnOptions, ExportData, TypedString};
 use core::iter;
 
 use crate::tokenizer::Span;
@@ -1525,7 +1525,7 @@ impl Spanned for Expr {
                 .union(&union_spans(collation.0.iter().map(|i| i.span()))),
             Expr::Nested(expr) => expr.span(),
             Expr::Value(value) => value.span(),
-            Expr::TypedString { value, .. } => value.span(),
+            Expr::TypedString(TypedString { value, .. }) => value.span(),
             Expr::Function(function) => function.span(),
             Expr::GroupingSets(vec) => {
                 union_spans(vec.iter().flat_map(|i| i.iter().map(|k| k.span())))

src/parser/mod.rs

@@ -1543,10 +1543,11 @@ impl<'a> Parser<'a> {
                 // an unary negation `NOT ('a' LIKE 'b')`. To solve this, we don't accept the
                 // `type 'string'` syntax for the custom data types at all.
                 DataType::Custom(..) => parser_err!("dummy", loc),
-                data_type => Ok(Expr::TypedString {
+                data_type => Ok(Expr::TypedString(TypedString {
                     data_type,
                     value: parser.parse_value()?,
-                }),
+                    uses_odbc_syntax: false,
+                })),
             }
         })?;
 
@@ -1732,10 +1733,11 @@ impl<'a> Parser<'a> {
     }
 
     fn parse_geometric_type(&mut self, kind: GeometricTypeKind) -> Result<Expr, ParserError> {
-        Ok(Expr::TypedString {
+        Ok(Expr::TypedString(TypedString {
             data_type: DataType::GeometricType(kind),
             value: self.parse_value()?,
-        })
+            uses_odbc_syntax: false,
+        }))
     }
 
     /// Try to parse an [Expr::CompoundFieldAccess] like `a.b.c` or `a.b[1].c`.
@@ -2032,6 +2034,50 @@ impl<'a> Parser<'a> {
         })
     }
 
+    /// Tries to parse the body of an [ODBC escaping sequence]
+    /// i.e. without the enclosing braces
+    /// Currently implemented:
+    /// Scalar Function Calls
+    /// Date, Time, and Timestamp Literals
+    /// See <https://learn.microsoft.com/en-us/sql/odbc/reference/develop-app/escape-sequences-in-odbc?view=sql-server-2017>
+    fn maybe_parse_odbc_body(&mut self) -> Result<Option<Expr>, ParserError> {
+        // Attempt 1: Try to parse it as a function.
+        if let Some(expr) = self.maybe_parse_odbc_fn_body()? {
+            return Ok(Some(expr));
+        }
+        // Attempt 2: Try to parse it as a Date, Time or Timestamp Literal
+        self.maybe_parse_odbc_body_datetime()
+    }
+
+    /// Tries to parse the body of an [ODBC Date, Time, and Timestamp Literals] call.
+    ///
+    /// ```sql
+    /// {d '2025-07-17'}
+    /// {t '14:12:01'}
+    /// {ts '2025-07-17 14:12:01'}
+    /// ```
+    ///
+    /// [ODBC Date, Time, and Timestamp Literals]:
+    /// https://learn.microsoft.com/en-us/sql/odbc/reference/develop-app/date-time-and-timestamp-literals?view=sql-server-2017
+    fn maybe_parse_odbc_body_datetime(&mut self) -> Result<Option<Expr>, ParserError> {
+        self.maybe_parse(|p| {
+            let token = p.next_token().clone();
+            let word_string = token.token.to_string();
+            let data_type = match word_string.as_str() {
+                "t" => DataType::Time(None, TimezoneInfo::None),
+                "d" => DataType::Date,
+                "ts" => DataType::Timestamp(None, TimezoneInfo::None),
+                _ => return p.expected("ODBC datetime keyword (t, d, or ts)", token),
+            };
+            let value = p.parse_value()?;
+            Ok(Expr::TypedString(TypedString {
+                data_type,
+                value,
+                uses_odbc_syntax: true,
+            }))
+        })
+    }
+
     /// Tries to parse the body of an [ODBC function] call.
     /// i.e. without the enclosing braces
     ///
@@ -2786,7 +2832,7 @@ impl<'a> Parser<'a> {
     fn parse_lbrace_expr(&mut self) -> Result<Expr, ParserError> {
         let token = self.expect_token(&Token::LBrace)?;
 
-        if let Some(fn_expr) = self.maybe_parse_odbc_fn_body()? {
+        if let Some(fn_expr) = self.maybe_parse_odbc_body()? {
             self.expect_token(&Token::RBrace)?;
             return Ok(fn_expr);
         }