Snowflake: parse MATCH_RECOGNIZE window semantics

src/ast/mod.rs

@@ -97,11 +97,11 @@ pub use self::query::{
     IlikeSelectItem, InputFormatClause, Interpolate, InterpolateExpr, Join, JoinConstraint,
     JoinOperator, JsonTableColumn, JsonTableColumnErrorHandling, JsonTableNamedColumn,
     JsonTableNestedColumn, LateralView, LimitClause, LockClause, LockType, MatchRecognizePattern,
-    MatchRecognizeSymbol, Measure, NamedWindowDefinition, NamedWindowExpr, NonBlock, Offset,
-    OffsetRows, OpenJsonTableColumn, OrderBy, OrderByExpr, OrderByKind, OrderByOptions,
-    PipeOperator, PivotValueSource, ProjectionSelect, Query, RenameSelectItem,
-    RepetitionQuantifier, ReplaceSelectElement, ReplaceSelectItem, RowsPerMatch, Select,
-    SelectFlavor, SelectInto, SelectItem, SelectItemQualifiedWildcardKind, SelectModifiers,
+    MatchRecognizeSymbol, MatchRecognizeWindowSemantic, Measure, NamedWindowDefinition,
+    NamedWindowExpr, NonBlock, Offset, OffsetRows, OpenJsonTableColumn, OrderBy, OrderByExpr,
+    OrderByKind, OrderByOptions, PipeOperator, PivotValueSource, ProjectionSelect, Query,
+    RenameSelectItem, RepetitionQuantifier, ReplaceSelectElement, ReplaceSelectItem, RowsPerMatch,
+    Select, SelectFlavor, SelectInto, SelectItem, SelectItemQualifiedWildcardKind, SelectModifiers,
     SetExpr, SetOperator, SetQuantifier, Setting, SymbolDefinition, Table, TableAlias,
     TableAliasColumnDef, TableFactor, TableFunctionArgs, TableIndexHintForClause,
     TableIndexHintType, TableIndexHints, TableIndexType, TableSample, TableSampleBucket,

src/ast/query.rs

@@ -1987,6 +1987,9 @@ impl fmt::Display for PivotValueSource {
 #[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
 /// An item in the `MEASURES` clause of `MATCH_RECOGNIZE`.
 pub struct Measure {
+    /// Explicit window-frame semantic for the measure.
+    #[cfg_attr(feature = "serde", serde(default))]
+    pub window_semantic: Option<MatchRecognizeWindowSemantic>,
     /// Expression producing the measure value.
     pub expr: Expr,
     /// Alias for the measure column.
@@ -1995,10 +1998,35 @@ pub struct Measure {
 
 impl fmt::Display for Measure {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if let Some(window_semantic) = self.window_semantic {
+            write!(f, "{window_semantic} ")?;
+        }
         write!(f, "{} AS {}", self.expr, self.alias)
     }
 }
 
+/// Window-frame semantic for a `MATCH_RECOGNIZE` measure.
+///
+/// See <https://docs.snowflake.com/en/sql-reference/constructs/match_recognize#label-match-recognize-navigational-functions>.
+#[derive(Debug, Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub enum MatchRecognizeWindowSemantic {
+    /// The frame ends at the current row.
+    Running,
+    /// The frame ends at the last row of the match.
+    Final,
+}
+
+impl fmt::Display for MatchRecognizeWindowSemantic {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Running => write!(f, "RUNNING"),
+            Self::Final => write!(f, "FINAL"),
+        }
+    }
+}
+
 /// The rows per match option in a `MATCH_RECOGNIZE` operation.
 ///
 /// See <https://docs.snowflake.com/en/sql-reference/constructs/match_recognize#row-s-per-match-specifying-the-rows-to-return>.

src/ast/spans.rs

@@ -2116,7 +2116,11 @@ impl Spanned for SymbolDefinition {
 
 impl Spanned for Measure {
     fn span(&self) -> Span {
-        let Measure { expr, alias } = self;
+        let Measure {
+            window_semantic: _,
+            expr,
+            alias,
+        } = self;
 
         expr.span().union(&alias.span)
     }

src/keywords.rs

@@ -911,6 +911,7 @@ define_keywords!(
     ROW_NUMBER,
     RULE,
     RUN,
+    RUNNING,
     SAFE,
     SAFE_CAST,
     SAMPLE,

src/parser/mod.rs

@@ -16709,10 +16709,21 @@ impl<'a> Parser<'a> {
 
         let measures = if self.parse_keyword(Keyword::MEASURES) {
             self.parse_comma_separated(|p| {
+                let window_semantic = if p.parse_keyword(Keyword::RUNNING) {
+                    Some(MatchRecognizeWindowSemantic::Running)
+                } else if p.parse_keyword(Keyword::FINAL) {
+                    Some(MatchRecognizeWindowSemantic::Final)
+                } else {
+                    None
+                };
                 let expr = p.parse_expr()?;
                 let _ = p.parse_keyword(Keyword::AS);
                 let alias = p.parse_identifier()?;
-                Ok(Measure { expr, alias })
+                Ok(Measure {
+                    window_semantic,
+                    expr,
+                    alias,
+                })
             })?
         } else {
             vec![]

tests/sqlparser_common.rs

@@ -13246,8 +13246,8 @@ fn test_match_recognize() {
             "ORDER BY price_date ",
             "MEASURES ",
             "MATCH_NUMBER() AS match_number, ",
-            "FIRST(price_date) AS start_date, ",
-            "LAST(price_date) AS end_date ",
+            "FINAL FIRST(price_date) AS start_date, ",
+            "RUNNING LAST(price_date) AS end_date ",
             "ONE ROW PER MATCH ",
             "AFTER MATCH SKIP TO LAST row_with_price_increase ",
             "PATTERN (row_before_decrease row_with_price_decrease+ row_with_price_increase+) ",
@@ -13268,14 +13268,17 @@ fn test_match_recognize() {
             }],
             measures: vec![
                 Measure {
+                    window_semantic: None,
                     expr: call("MATCH_NUMBER", []),
                     alias: Ident::new("match_number"),
                 },
                 Measure {
+                    window_semantic: Some(MatchRecognizeWindowSemantic::Final),
                     expr: call("FIRST", [Expr::Identifier(Ident::new("price_date"))]),
                     alias: Ident::new("start_date"),
                 },
                 Measure {
+                    window_semantic: Some(MatchRecognizeWindowSemantic::Running),
                     expr: call("LAST", [Expr::Identifier(Ident::new("price_date"))]),
                     alias: Ident::new("end_date"),
                 },