ISSUE-1088: Fix array_agg wildcard behavior (#1093)

Co-authored-by: Andrew Repp <arepp@cloudflare.com>

Author: ReppCodes

src/ast/mod.rs

@@ -380,7 +380,10 @@ pub enum Expr {
         right: Box<Expr>,
     },
     /// CompositeAccess (postgres) eg: SELECT (information_schema._pg_expandarray(array['i','i'])).n
-    CompositeAccess { expr: Box<Expr>, key: Ident },
+    CompositeAccess {
+        expr: Box<Expr>,
+        key: Ident,
+    },
     /// `IS FALSE` operator
     IsFalse(Box<Expr>),
     /// `IS NOT FALSE` operator
@@ -474,7 +477,10 @@ pub enum Expr {
         right: Box<Expr>,
     },
     /// Unary operation e.g. `NOT foo`
-    UnaryOp { op: UnaryOperator, expr: Box<Expr> },
+    UnaryOp {
+        op: UnaryOperator,
+        expr: Box<Expr>,
+    },
     /// CONVERT a value to a different data type or character encoding. e.g. `CONVERT(foo USING utf8mb4)`
     Convert {
         /// The expression to convert
@@ -545,7 +551,10 @@ pub enum Expr {
     /// ```sql
     /// POSITION(<expr> in <expr>)
     /// ```
-    Position { expr: Box<Expr>, r#in: Box<Expr> },
+    Position {
+        expr: Box<Expr>,
+        r#in: Box<Expr>,
+    },
     /// ```sql
     /// SUBSTRING(<expr> [FROM <expr>] [FOR <expr>])
     /// ```
@@ -589,20 +598,32 @@ pub enum Expr {
     /// A literal value, such as string, number, date or NULL
     Value(Value),
     /// <https://dev.mysql.com/doc/refman/8.0/en/charset-introducer.html>
-    IntroducedString { introducer: String, value: Value },
+    IntroducedString {
+        introducer: String,
+        value: Value,
+    },
     /// 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, value: String },
+    TypedString {
+        data_type: DataType,
+        value: String,
+    },
     /// Access a map-like object by field (e.g. `column['field']` or `column[4]`
     /// Note that depending on the dialect, struct like accesses may be
     /// parsed as [`ArrayIndex`](Self::ArrayIndex) or [`MapAccess`](Self::MapAccess)
     /// <https://clickhouse.com/docs/en/sql-reference/data-types/map/>
-    MapAccess { column: Box<Expr>, keys: Vec<Expr> },
+    MapAccess {
+        column: Box<Expr>,
+        keys: Vec<Expr>,
+    },
     /// Scalar function call e.g. `LEFT(foo, 5)`
     Function(Function),
     /// Aggregate function with filter
-    AggregateExpressionWithFilter { expr: Box<Expr>, filter: Box<Expr> },
+    AggregateExpressionWithFilter {
+        expr: Box<Expr>,
+        filter: Box<Expr>,
+    },
     /// `CASE [<operand>] WHEN <condition> THEN <result> ... [ELSE <result>] END`
     ///
     /// Note we only recognize a complete single expression as `<condition>`,
@@ -616,7 +637,10 @@ pub enum Expr {
     },
     /// An exists expression `[ NOT ] EXISTS(SELECT ...)`, used in expressions like
     /// `WHERE [ NOT ] EXISTS (SELECT ...)`.
-    Exists { subquery: Box<Query>, negated: bool },
+    Exists {
+        subquery: Box<Query>,
+        negated: bool,
+    },
     /// A parenthesized subquery `(SELECT ...)`, used in expression like
     /// `SELECT (subquery) AS x` or `WHERE (subquery) = x`
     Subquery(Box<Query>),
@@ -653,9 +677,15 @@ pub enum Expr {
     /// 1 AS A
     /// ```
     /// [1]: https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#struct_type
-    Named { expr: Box<Expr>, name: Ident },
+    Named {
+        expr: Box<Expr>,
+        name: Ident,
+    },
     /// An array index expression e.g. `(ARRAY[1, 2])[1]` or `(current_schemas(FALSE))[1]`
-    ArrayIndex { obj: Box<Expr>, indexes: Vec<Expr> },
+    ArrayIndex {
+        obj: Box<Expr>,
+        indexes: Vec<Expr>,
+    },
     /// An array expression e.g. `ARRAY[1, 2]`
     Array(Array),
     /// An interval expression e.g. `INTERVAL '1' YEAR`
@@ -678,6 +708,10 @@ pub enum Expr {
         /// `<search modifier>`
         opt_search_modifier: Option<SearchModifier>,
     },
+    Wildcard,
+    /// Qualified wildcard, e.g. `alias.*` or `schema.table.*`.
+    /// (Same caveats apply to `QualifiedWildcard` as to `Wildcard`.)
+    QualifiedWildcard(ObjectName),
 }
 
 impl fmt::Display for CastFormat {
@@ -704,6 +738,8 @@ impl fmt::Display for Expr {
                 }
                 Ok(())
             }
+            Expr::Wildcard => f.write_str("*"),
+            Expr::QualifiedWildcard(prefix) => write!(f, "{}.*", prefix),
             Expr::CompoundIdentifier(s) => write!(f, "{}", display_separated(s, ".")),
             Expr::IsTrue(ast) => write!(f, "{ast} IS TRUE"),
             Expr::IsNotTrue(ast) => write!(f, "{ast} IS NOT TRUE"),
@@ -4188,6 +4224,16 @@ pub enum FunctionArgExpr {
     Wildcard,
 }
 
+impl From<Expr> for FunctionArgExpr {
+    fn from(wildcard_expr: Expr) -> Self {
+        match wildcard_expr {
+            Expr::QualifiedWildcard(prefix) => Self::QualifiedWildcard(prefix),
+            Expr::Wildcard => Self::Wildcard,
+            expr => Self::Expr(expr),
+        }
+    }
+}
+
 impl fmt::Display for FunctionArgExpr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {

src/parser/mod.rs

@@ -161,16 +161,6 @@ pub enum WildcardExpr {
     Wildcard,
 }
 
-impl From<WildcardExpr> for FunctionArgExpr {
-    fn from(wildcard_expr: WildcardExpr) -> Self {
-        match wildcard_expr {
-            WildcardExpr::Expr(expr) => Self::Expr(expr),
-            WildcardExpr::QualifiedWildcard(prefix) => Self::QualifiedWildcard(prefix),
-            WildcardExpr::Wildcard => Self::Wildcard,
-        }
-    }
-}
-
 impl From<TokenizerError> for ParserError {
     fn from(e: TokenizerError) -> Self {
         ParserError::TokenizerError(e.to_string())
@@ -734,7 +724,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parse a new expression including wildcard & qualified wildcard
-    pub fn parse_wildcard_expr(&mut self) -> Result<WildcardExpr, ParserError> {
+    pub fn parse_wildcard_expr(&mut self) -> Result<Expr, ParserError> {
         let index = self.index;
 
         let next_token = self.next_token();
@@ -756,7 +746,7 @@ impl<'a> Parser<'a> {
                                 id_parts.push(Ident::with_quote('\'', s))
                             }
                             Token::Mul => {
-                                return Ok(WildcardExpr::QualifiedWildcard(ObjectName(id_parts)));
+                                return Ok(Expr::QualifiedWildcard(ObjectName(id_parts)));
                             }
                             _ => {
                                 return self
@@ -767,13 +757,13 @@ impl<'a> Parser<'a> {
                 }
             }
             Token::Mul => {
-                return Ok(WildcardExpr::Wildcard);
+                return Ok(Expr::Wildcard);
             }
             _ => (),
         };
 
         self.index = index;
-        self.parse_expr().map(WildcardExpr::Expr)
+        self.parse_expr()
     }
 
     /// Parse a new expression
@@ -969,10 +959,22 @@ impl<'a> Parser<'a> {
                 _ => match self.peek_token().token {
                     Token::LParen | Token::Period => {
                         let mut id_parts: Vec<Ident> = vec![w.to_ident()];
+                        let mut ends_with_wildcard = false;
                         while self.consume_token(&Token::Period) {
                             let next_token = self.next_token();
                             match next_token.token {
                                 Token::Word(w) => id_parts.push(w.to_ident()),
+                                Token::Mul => {
+                                    // Postgres explicitly allows funcnm(tablenm.*) and the
+                                    // function array_agg traverses this control flow
+                                    if dialect_of!(self is PostgreSqlDialect) {
+                                        ends_with_wildcard = true;
+                                        break;
+                                    } else {
+                                        return self
+                                            .expected("an identifier after '.'", next_token);
+                                    }
+                                }
                                 Token::SingleQuotedString(s) => {
                                     id_parts.push(Ident::with_quote('\'', s))
                                 }
@@ -983,7 +985,9 @@ impl<'a> Parser<'a> {
                             }
                         }
 
-                        if self.consume_token(&Token::LParen) {
+                        if ends_with_wildcard {
+                            Ok(Expr::QualifiedWildcard(ObjectName(id_parts)))
+                        } else if self.consume_token(&Token::LParen) {
                             self.prev_token();
                             self.parse_function(ObjectName(id_parts))
                         } else {
@@ -8051,9 +8055,9 @@ impl<'a> Parser<'a> {
                 let subquery = self.parse_query()?;
                 self.expect_token(&Token::RParen)?;
                 return Ok((
-                    vec![FunctionArg::Unnamed(FunctionArgExpr::from(
-                        WildcardExpr::Expr(Expr::Subquery(Box::new(subquery))),
-                    ))],
+                    vec![FunctionArg::Unnamed(FunctionArgExpr::from(Expr::Subquery(
+                        Box::new(subquery),
+                    )))],
                     vec![],
                 ));
             }
@@ -8072,7 +8076,14 @@ impl<'a> Parser<'a> {
     /// Parse a comma-delimited list of projections after SELECT
     pub fn parse_select_item(&mut self) -> Result<SelectItem, ParserError> {
         match self.parse_wildcard_expr()? {
-            WildcardExpr::Expr(expr) => {
+            Expr::QualifiedWildcard(prefix) => Ok(SelectItem::QualifiedWildcard(
+                prefix,
+                self.parse_wildcard_additional_options()?,
+            )),
+            Expr::Wildcard => Ok(SelectItem::Wildcard(
+                self.parse_wildcard_additional_options()?,
+            )),
+            expr => {
                 let expr: Expr = if self.dialect.supports_filter_during_aggregation()
                     && self.parse_keyword(Keyword::FILTER)
                 {
@@ -8097,13 +8108,6 @@ impl<'a> Parser<'a> {
                         None => SelectItem::UnnamedExpr(expr),
                     })
             }
-            WildcardExpr::QualifiedWildcard(prefix) => Ok(SelectItem::QualifiedWildcard(
-                prefix,
-                self.parse_wildcard_additional_options()?,
-            )),
-            WildcardExpr::Wildcard => Ok(SelectItem::Wildcard(
-                self.parse_wildcard_additional_options()?,
-            )),
         }
     }
 

tests/sqlparser_common.rs

@@ -2403,6 +2403,12 @@ fn parse_array_agg_func() {
     ] {
         supported_dialects.verified_stmt(sql);
     }
+
+    // follows special-case array_agg code path. fails in everything except postgres
+    let wc_sql = "SELECT ARRAY_AGG(sections_tbl.*) AS sections FROM sections_tbl";
+    all_dialects_but_pg()
+        .parse_sql_statements(wc_sql)
+        .expect_err("should have failed");
 }
 
 #[test]

tests/sqlparser_postgres.rs

@@ -3800,3 +3800,22 @@ fn test_simple_insert_with_quoted_alias() {
         }
     )
 }
+
+#[test]
+fn parse_array_agg() {
+    // follows general function with wildcard code path
+    let sql = r#"SELECT GREATEST(sections_tbl.*) AS sections FROM sections_tbl"#;
+    pg().verified_stmt(sql);
+
+    // follows special-case array_agg code path
+    let sql2 = "SELECT ARRAY_AGG(sections_tbl.*) AS sections FROM sections_tbl";
+    pg().verified_stmt(sql2);
+
+    // handles multi-part identifier with general code path
+    let sql3 = "SELECT GREATEST(my_schema.sections_tbl.*) AS sections FROM sections_tbl";
+    pg().verified_stmt(sql3);
+
+    // handles multi-part identifier with array_agg code path
+    let sql4 = "SELECT ARRAY_AGG(my_schema.sections_tbl.*) AS sections FROM sections_tbl";
+    pg().verified_stmt(sql4);
+}