Support DuckDB struct syntax and support list of struct syntax

.gitignore

@@ -16,3 +16,5 @@ Cargo.lock
 .vscode
 
 *.swp
+
+.DS_store

src/ast/data_type.rs

@@ -302,7 +302,7 @@ pub enum DataType {
     ///
     /// [hive]: https://docs.cloudera.com/cdw-runtime/cloud/impala-sql-reference/topics/impala-struct.html
     /// [bigquery]: https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#struct_type
-    Struct(Vec<StructField>),
+    Struct(Vec<StructField>, StructBracketKind),
     /// Union
     ///
     /// [duckdb]: https://duckdb.org/docs/sql/data_types/union.html
@@ -517,9 +517,16 @@ impl fmt::Display for DataType {
                 }
                 write!(f, ")")
             }
-            DataType::Struct(fields) => {
+            DataType::Struct(fields, bracket) => {
                 if !fields.is_empty() {
-                    write!(f, "STRUCT<{}>", display_comma_separated(fields))
+                    match bracket {
+                        StructBracketKind::Parentheses => {
+                            write!(f, "STRUCT({})", display_comma_separated(fields))
+                        }
+                        StructBracketKind::AngleBrackets => {
+                            write!(f, "STRUCT<{}>", display_comma_separated(fields))
+                        }
+                    }
                 } else {
                     write!(f, "STRUCT")
                 }
@@ -618,6 +625,17 @@ fn format_clickhouse_datetime_precision_and_timezone(
     Ok(())
 }
 
+/// Type of brackets used for `STRUCT` literals.
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub enum StructBracketKind {
+    /// Example: `STRUCT(a INT, b STRING)`
+    Parentheses,
+    /// Example: `STRUCT<a INT, b STRING>`
+    AngleBrackets,
+}
+
 /// Timestamp and Time data types information about TimeZone formatting.
 ///
 /// This is more related to a display information than real differences between each variant. To

src/ast/mod.rs

@@ -28,7 +28,8 @@ use serde::{Deserialize, Serialize};
 use sqlparser_derive::{Visit, VisitMut};
 
 pub use self::data_type::{
-    ArrayElemTypeDef, CharLengthUnits, CharacterLength, DataType, ExactNumberInfo, TimezoneInfo,
+    ArrayElemTypeDef, CharLengthUnits, CharacterLength, DataType, ExactNumberInfo,
+    StructBracketKind, TimezoneInfo,
 };
 pub use self::dcl::{AlterRoleOperation, ResetConfig, RoleOption, SetConfigValue};
 pub use self::ddl::{

src/parser/mod.rs

@@ -2266,6 +2266,23 @@ impl<'a> Parser<'a> {
         ))
     }
 
+    /// Duckdb Struct Data Type <https://duckdb.org/docs/sql/data_types/struct.html#retrieving-from-structs>
+    fn parse_duckdb_struct_type_def(&mut self) -> Result<Vec<StructField>, ParserError> {
+        self.expect_keyword(Keyword::STRUCT)?;
+        self.expect_token(&Token::LParen)?;
+        let struct_body = self.parse_comma_separated(|parser| {
+            let field_name = parser.parse_identifier(false)?;
+            let field_type = parser.parse_data_type()?;
+
+            Ok(StructField {
+                field_name: Some(field_name),
+                field_type,
+            })
+        });
+        self.expect_token(&Token::RParen)?;
+        struct_body
+    }
+
     /// Parse a field definition in a [struct] or [tuple].
     /// Syntax:
     ///
@@ -7495,12 +7512,20 @@ impl<'a> Parser<'a> {
                         ))))
                     }
                 }
+                Keyword::STRUCT if dialect_of!(self is DuckDbDialect) => {
+                    self.prev_token();
+                    let field_defs = self.parse_duckdb_struct_type_def()?;
+                    Ok(DataType::Struct(field_defs, StructBracketKind::Parentheses))
+                }
                 Keyword::STRUCT if dialect_of!(self is BigQueryDialect | GenericDialect) => {
                     self.prev_token();
                     let (field_defs, _trailing_bracket) =
                         self.parse_struct_type_def(Self::parse_struct_field_def)?;
                     trailing_bracket = _trailing_bracket;
-                    Ok(DataType::Struct(field_defs))
+                    Ok(DataType::Struct(
+                        field_defs,
+                        StructBracketKind::AngleBrackets,
+                    ))
                 }
                 Keyword::UNION if dialect_of!(self is DuckDbDialect | GenericDialect) => {
                     self.prev_token();

tests/sqlparser_bigquery.rs

@@ -489,28 +489,34 @@ fn parse_nested_data_types() {
                 vec![
                     ColumnDef {
                         name: Ident::new("x"),
-                        data_type: DataType::Struct(vec![
-                            StructField {
-                                field_name: Some("a".into()),
-                                field_type: DataType::Array(ArrayElemTypeDef::AngleBracket(
-                                    Box::new(DataType::Int64,)
-                                ))
-                            },
-                            StructField {
-                                field_name: Some("b".into()),
-                                field_type: DataType::Bytes(Some(42))
-                            },
-                        ]),
+                        data_type: DataType::Struct(
+                            vec![
+                                StructField {
+                                    field_name: Some("a".into()),
+                                    field_type: DataType::Array(ArrayElemTypeDef::AngleBracket(
+                                        Box::new(DataType::Int64,)
+                                    ))
+                                },
+                                StructField {
+                                    field_name: Some("b".into()),
+                                    field_type: DataType::Bytes(Some(42))
+                                },
+                            ],
+                            StructBracketKind::AngleBrackets
+                        ),
                         collation: None,
                         options: vec![],
                     },
                     ColumnDef {
                         name: Ident::new("y"),
                         data_type: DataType::Array(ArrayElemTypeDef::AngleBracket(Box::new(
-                            DataType::Struct(vec![StructField {
-                                field_name: None,
-                                field_type: DataType::Int64,
-                            }]),
+                            DataType::Struct(
+                                vec![StructField {
+                                    field_name: None,
+                                    field_type: DataType::Int64,
+                                }],
+                                StructBracketKind::AngleBrackets
+                            ),
                         ))),
                         collation: None,
                         options: vec![],
@@ -708,10 +714,13 @@ fn parse_typed_struct_syntax_bigquery() {
                 },
                 StructField {
                     field_name: Some("str".into()),
-                    field_type: DataType::Struct(vec![StructField {
-                        field_name: None,
-                        field_type: DataType::Bool
-                    }])
+                    field_type: DataType::Struct(
+                        vec![StructField {
+                            field_name: None,
+                            field_type: DataType::Bool
+                        }],
+                        StructBracketKind::AngleBrackets
+                    )
                 },
             ]
         },
@@ -730,12 +739,15 @@ fn parse_typed_struct_syntax_bigquery() {
             fields: vec![
                 StructField {
                     field_name: Some("x".into()),
-                    field_type: DataType::Struct(Default::default())
+                    field_type: DataType::Struct(
+                        Default::default(),
+                        StructBracketKind::AngleBrackets
+                    )
                 },
                 StructField {
                     field_name: Some("y".into()),
                     field_type: DataType::Array(ArrayElemTypeDef::AngleBracket(Box::new(
-                        DataType::Struct(Default::default())
+                        DataType::Struct(Default::default(), StructBracketKind::AngleBrackets)
                     )))
                 },
             ]
@@ -1013,10 +1025,13 @@ fn parse_typed_struct_syntax_bigquery_and_generic() {
                 },
                 StructField {
                     field_name: Some("str".into()),
-                    field_type: DataType::Struct(vec![StructField {
-                        field_name: None,
-                        field_type: DataType::Bool
-                    }])
+                    field_type: DataType::Struct(
+                        vec![StructField {
+                            field_name: None,
+                            field_type: DataType::Bool
+                        }],
+                        StructBracketKind::AngleBrackets
+                    )
                 },
             ]
         },
@@ -1035,12 +1050,15 @@ fn parse_typed_struct_syntax_bigquery_and_generic() {
             fields: vec![
                 StructField {
                     field_name: Some("x".into()),
-                    field_type: DataType::Struct(Default::default())
+                    field_type: DataType::Struct(
+                        Default::default(),
+                        StructBracketKind::AngleBrackets
+                    )
                 },
                 StructField {
                     field_name: Some("y".into()),
                     field_type: DataType::Array(ArrayElemTypeDef::AngleBracket(Box::new(
-                        DataType::Struct(Default::default())
+                        DataType::Struct(Default::default(), StructBracketKind::AngleBrackets)
                     )))
                 },
             ]

tests/sqlparser_duckdb.rs

@@ -32,6 +32,118 @@ fn duckdb_and_generic() -> TestedDialects {
     }
 }
 
+#[test]
+fn test_struct() {
+    // s STRUCT(v VARCHAR, i INTEGER)
+    let struct_type1 = DataType::Struct(
+        vec![
+            StructField {
+                field_name: Some(Ident::new("v")),
+                field_type: DataType::Varchar(None),
+            },
+            StructField {
+                field_name: Some(Ident::new("i")),
+                field_type: DataType::Integer(None),
+            },
+        ],
+        StructBracketKind::Parentheses,
+    );
+
+    // basic struct
+    let statement = duckdb().verified_stmt(r#"CREATE TABLE t1 (s STRUCT(v VARCHAR, i INTEGER))"#);
+    assert_eq!(
+        column_defs(statement),
+        vec![ColumnDef {
+            name: "s".into(),
+            data_type: struct_type1.clone(),
+            collation: None,
+            options: vec![],
+        }]
+    );
+
+    // struct array
+    let statement = duckdb().verified_stmt(r#"CREATE TABLE t1 (s STRUCT(v VARCHAR, i INTEGER)[])"#);
+    assert_eq!(
+        column_defs(statement),
+        vec![ColumnDef {
+            name: "s".into(),
+            data_type: DataType::Array(ArrayElemTypeDef::SquareBracket(
+                Box::new(struct_type1),
+                None
+            )),
+            collation: None,
+            options: vec![],
+        }]
+    );
+
+    // s STRUCT(v VARCHAR, s STRUCT(a1 INTEGER, a2 VARCHAR))
+    let struct_type2 = DataType::Struct(
+        vec![
+            StructField {
+                field_name: Some(Ident::new("v")),
+                field_type: DataType::Varchar(None),
+            },
+            StructField {
+                field_name: Some(Ident::new("s")),
+                field_type: DataType::Struct(
+                    vec![
+                        StructField {
+                            field_name: Some(Ident::new("a1")),
+                            field_type: DataType::Integer(None),
+                        },
+                        StructField {
+                            field_name: Some(Ident::new("a2")),
+                            field_type: DataType::Varchar(None),
+                        },
+                    ],
+                    StructBracketKind::Parentheses,
+                ),
+            },
+        ],
+        StructBracketKind::Parentheses,
+    );
+
+    // nested struct
+    let statement = duckdb().verified_stmt(
+        r#"CREATE TABLE t1 (s STRUCT(v VARCHAR, s STRUCT(a1 INTEGER, a2 VARCHAR))[])"#,
+    );
+
+    assert_eq!(
+        column_defs(statement),
+        vec![ColumnDef {
+            name: "s".into(),
+            data_type: DataType::Array(ArrayElemTypeDef::SquareBracket(
+                Box::new(struct_type2),
+                None
+            )),
+            collation: None,
+            options: vec![],
+        }]
+    );
+
+    // failing test (duckdb does not support bracket syntax)
+    let sql_list = vec![
+        r#"CREATE TABLE t1 (s STRUCT(v VARCHAR, i INTEGER)))"#,
+        r#"CREATE TABLE t1 (s STRUCT(v VARCHAR, i INTEGER>)"#,
+        r#"CREATE TABLE t1 (s STRUCT<v VARCHAR, i INTEGER>)"#,
+        r#"CREATE TABLE t1 (s STRUCT v VARCHAR, i INTEGER )"#,
+        r#"CREATE TABLE t1 (s STRUCT VARCHAR, i INTEGER )"#,
+        r#"CREATE TABLE t1 (s STRUCT (VARCHAR, INTEGER))"#,
+    ];
+
+    for sql in sql_list {
+        duckdb().parse_sql_statements(sql).unwrap_err();
+    }
+}
+
+/// Returns the ColumnDefinitions from a CreateTable statement
+fn column_defs(statement: Statement) -> Vec<ColumnDef> {
+    match statement {
+        Statement::CreateTable(CreateTable { columns, .. }) => columns,
+        _ => panic!("Expected CreateTable"),
+    }
+}
+
 #[test]
 fn test_select_wildcard_with_exclude() {
     let select = duckdb().verified_only_select("SELECT * EXCLUDE (col_a) FROM data");