PostgreSQL: Support CREATE FOREIGN TABLE

src/ast/ddl.rs

@@ -42,15 +42,15 @@ use crate::ast::{
         UniqueConstraint,
     },
     ArgMode, AttachedToken, CommentDef, ConditionalStatements, CreateFunctionBody,
-    CreateFunctionUsing, CreateTableLikeKind, CreateTableOptions, CreateViewParams, DataType, Expr,
-    FileFormat, FunctionBehavior, FunctionCalledOnNull, FunctionDefinitionSetParam, FunctionDesc,
-    FunctionDeterminismSpecifier, FunctionParallel, FunctionSecurity, HiveDistributionStyle,
-    HiveFormat, HiveIOFormat, HiveRowFormat, HiveSetLocation, Ident, InitializeKind,
-    MySQLColumnPosition, ObjectName, OnCommit, OneOrManyWithParens, OperateFunctionArg,
-    OrderByExpr, ProjectionSelect, Query, RefreshModeKind, ResetConfig, RowAccessPolicy,
-    SequenceOptions, Spanned, SqlOption, StorageLifecyclePolicy, StorageSerializationPolicy,
-    TableVersion, Tag, TriggerEvent, TriggerExecBody, TriggerObject, TriggerPeriod,
-    TriggerReferencing, Value, ValueWithSpan, WrappedCollection,
+    CreateFunctionUsing, CreateServerOption, CreateTableLikeKind, CreateTableOptions,
+    CreateViewParams, DataType, Expr, FileFormat, FunctionBehavior, FunctionCalledOnNull,
+    FunctionDefinitionSetParam, FunctionDesc, FunctionDeterminismSpecifier, FunctionParallel,
+    FunctionSecurity, HiveDistributionStyle, HiveFormat, HiveIOFormat, HiveRowFormat,
+    HiveSetLocation, Ident, InitializeKind, MySQLColumnPosition, ObjectName, OnCommit,
+    OneOrManyWithParens, OperateFunctionArg, OrderByExpr, ProjectionSelect, Query, RefreshModeKind,
+    ResetConfig, RowAccessPolicy, SequenceOptions, Spanned, SqlOption, StorageLifecyclePolicy,
+    StorageSerializationPolicy, TableVersion, Tag, TriggerEvent, TriggerExecBody, TriggerObject,
+    TriggerPeriod, TriggerReferencing, Value, ValueWithSpan, WrappedCollection,
 };
 use crate::display_utils::{DisplayCommaSeparated, Indent, NewLine, SpaceOrNewline};
 use crate::keywords::Keyword;
@@ -5995,3 +5995,75 @@ impl From<AlterPolicy> for crate::ast::Statement {
         crate::ast::Statement::AlterPolicy(v)
     }
 }
+
+/// A `CREATE FOREIGN TABLE` statement.
+///
+/// See [PostgreSQL](https://www.postgresql.org/docs/current/sql-createforeigntable.html)
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+pub struct CreateForeignTable {
+    /// The foreign table name.
+    #[cfg_attr(feature = "visitor", visit(with = "visit_relation"))]
+    pub name: ObjectName,
+    /// Whether `IF NOT EXISTS` was specified.
+    pub if_not_exists: bool,
+    /// Column definitions.
+    pub columns: Vec<ColumnDef>,
+    /// Table-level constraints (e.g. `CHECK (...)`, composite `FOREIGN KEY`).
+    /// PostgreSQL's grammar accepts these here, but rejects primary key, unique,
+    /// foreign key and exclusion constraints on a foreign table at execution.
+    pub constraints: Vec<TableConstraint>,
+    /// The `SERVER server_name` clause.
+    pub server_name: Ident,
+    /// Optional `OPTIONS (key 'value', ...)` clause at the table level.
+    pub options: Option<Vec<CreateServerOption>>,
+}
+
+impl fmt::Display for CreateForeignTable {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "CREATE FOREIGN TABLE {if_not_exists}{name} ({columns}",
+            if_not_exists = if self.if_not_exists {
+                "IF NOT EXISTS "
+            } else {
+                ""
+            },
+            name = self.name,
+            columns = display_comma_separated(&self.columns),
+        )?;
+        if !self.columns.is_empty() && !self.constraints.is_empty() {
+            write!(f, ", ")?;
+        }
+        write!(f, "{}", display_comma_separated(&self.constraints))?;
+        write!(f, ") SERVER {}", self.server_name)?;
+        if let Some(options) = &self.options {
+            write!(f, " OPTIONS ({})", display_comma_separated(options))?;
+        }
+        Ok(())
+    }
+}
+
+impl From<CreateForeignTable> for crate::ast::Statement {
+    fn from(v: CreateForeignTable) -> Self {
+        crate::ast::Statement::CreateForeignTable(v)
+    }
+}
+
+impl Spanned for CreateForeignTable {
+    fn span(&self) -> Span {
+        Span::union_iter(
+            core::iter::once(self.name.span())
+                .chain(self.columns.iter().map(|column| column.span()))
+                .chain(self.constraints.iter().map(|constraint| constraint.span()))
+                .chain(core::iter::once(self.server_name.span))
+                .chain(
+                    self.options
+                        .iter()
+                        .flatten()
+                        .flat_map(|option| [option.key.span, option.value.span]),
+                ),
+        )
+    }
+}

src/ast/mod.rs

@@ -72,7 +72,7 @@ pub use self::ddl::{
     AlterTypeOperation, AlterTypeRename, AlterTypeRenameValue, ClusteredBy, ColumnDef,
     ColumnOption, ColumnOptionDef, ColumnOptions, ColumnPolicy, ColumnPolicyProperty,
     ConstraintCharacteristics, CreateCollation, CreateCollationDefinition, CreateConnector,
-    CreateDomain, CreateExtension, CreateFunction, CreateIndex, CreateOperator,
+    CreateDomain, CreateExtension, CreateForeignTable, CreateFunction, CreateIndex, CreateOperator,
     CreateOperatorClass, CreateOperatorFamily, CreatePolicy, CreatePolicyCommand, CreatePolicyType,
     CreateTable, CreateTextSearch, CreateTrigger, CreateView, Deduplicate, DeferrableInitial,
     DistStyle, DropBehavior, DropExtension, DropFunction, DropOperator, DropOperatorClass,
@@ -3773,6 +3773,11 @@ pub enum Statement {
     /// A `CREATE SERVER` statement.
     CreateServer(CreateServerStatement),
     /// ```sql
+    /// CREATE FOREIGN TABLE
+    /// ```
+    /// See [PostgreSQL](https://www.postgresql.org/docs/current/sql-createforeigntable.html)
+    CreateForeignTable(CreateForeignTable),
+    /// ```sql
     /// CREATE POLICY
     /// ```
     /// See [PostgreSQL](https://www.postgresql.org/docs/current/sql-createpolicy.html)
@@ -5632,6 +5637,7 @@ impl fmt::Display for Statement {
             Statement::CreateServer(stmt) => {
                 write!(f, "{stmt}")
             }
+            Statement::CreateForeignTable(stmt) => write!(f, "{stmt}"),
             Statement::CreatePolicy(policy) => write!(f, "{policy}"),
             Statement::CreateConnector(create_connector) => create_connector.fmt(f),
             Statement::CreateOperator(create_operator) => create_operator.fmt(f),
@@ -9189,7 +9195,7 @@ impl fmt::Display for CreateServerStatement {
     }
 }
 
-/// A key/value option for `CREATE SERVER`.
+/// A key/value entry in a Postgres `OPTIONS ( ... )` clause.
 #[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]

src/ast/spans.rs

@@ -394,6 +394,7 @@ impl Spanned for Statement {
             Statement::DropOperatorClass(drop_operator_class) => drop_operator_class.span(),
             Statement::CreateSecret { .. } => Span::empty(),
             Statement::CreateServer { .. } => Span::empty(),
+            Statement::CreateForeignTable(stmt) => stmt.span(),
             Statement::CreateConnector { .. } => Span::empty(),
             Statement::CreateOperator(create_operator) => create_operator.span(),
             Statement::CreateOperatorFamily(create_operator_family) => {
@@ -3163,4 +3164,19 @@ WHERE id = 1
             Span::new(Location::new(2, 8), Location::new(4, 52))
         );
     }
+
+    #[test]
+    fn test_create_foreign_table_span_includes_option_keys() {
+        let dialect = &crate::dialect::PostgreSqlDialect {};
+        let sql = "CREATE FOREIGN TABLE ft (a INT) SERVER s OPTIONS (schema_name 'public')";
+        let mut test = SpanTest::new(dialect, sql);
+
+        // Ends at the option key, not the statement: a quoted option value is an
+        // Ident with an empty span, so it contributes nothing to the union.
+        let stmt = test.0.parse_statement().unwrap();
+        assert_eq!(
+            test.get_source(stmt.span()),
+            "ft (a INT) SERVER s OPTIONS (schema_name"
+        );
+    }
 }

src/parser/mod.rs

@@ -5257,6 +5257,7 @@ impl<'a> Parser<'a> {
 
     /// Parse a SQL CREATE statement
     pub fn parse_create(&mut self) -> Result<Statement, ParserError> {
+        let modifier_loc = self.peek_token_ref().span.start;
         let or_replace = self.parse_keywords(&[Keyword::OR, Keyword::REPLACE]);
         let or_alter = self.parse_keywords(&[Keyword::OR, Keyword::ALTER]);
         let multiset = self.maybe_parse_multiset();
@@ -5359,6 +5360,25 @@ impl<'a> Parser<'a> {
             }
         } else if self.parse_keyword(Keyword::SERVER) {
             self.parse_pg_create_server()
+        } else if self.parse_keywords(&[Keyword::FOREIGN, Keyword::TABLE]) {
+            // `or_replace` cannot reach here today, since the arm above catches it.
+            // It stays so that reordering the arms cannot make it fall through.
+            if or_replace
+                || or_alter
+                || temporary
+                || global.is_some()
+                || transient
+                || volatile
+                || multiset.is_some()
+                || persistent
+                || create_view_params.is_some()
+            {
+                return parser_err!(
+                    "CREATE FOREIGN TABLE does not accept this modifier",
+                    modifier_loc
+                );
+            }
+            self.parse_create_foreign_table().map(Into::into)
         } else {
             self.expected_ref("an object type after CREATE", self.peek_token_ref())
         }
@@ -20431,16 +20451,7 @@ impl<'a> Parser<'a> {
         self.expect_keywords(&[Keyword::FOREIGN, Keyword::DATA, Keyword::WRAPPER])?;
         let foreign_data_wrapper = self.parse_object_name(false)?;
 
-        let mut options = None;
-        if self.parse_keyword(Keyword::OPTIONS) {
-            self.expect_token(&Token::LParen)?;
-            options = Some(self.parse_comma_separated(|p| {
-                let key = p.parse_identifier()?;
-                let value = p.parse_identifier()?;
-                Ok(CreateServerOption { key, value })
-            })?);
-            self.expect_token(&Token::RParen)?;
-        }
+        let options = self.parse_pg_options_clause()?;
 
         Ok(Statement::CreateServer(CreateServerStatement {
             name,
@@ -20452,6 +20463,51 @@ impl<'a> Parser<'a> {
         }))
     }
 
+    /// Parse an optional Postgres `OPTIONS ( key value [, ...] )` clause.
+    fn parse_pg_options_clause(&mut self) -> Result<Option<Vec<CreateServerOption>>, ParserError> {
+        if !self.parse_keyword(Keyword::OPTIONS) {
+            return Ok(None);
+        }
+        self.expect_token(&Token::LParen)?;
+        let options = self.parse_comma_separated(|p| {
+            let key = p.parse_identifier()?;
+            let value = p.parse_identifier()?;
+            Ok(CreateServerOption { key, value })
+        })?;
+        self.expect_token(&Token::RParen)?;
+        Ok(Some(options))
+    }
+
+    /// Parse a `CREATE FOREIGN TABLE` statement.
+    ///
+    /// Per-column `OPTIONS ( ... )`, `INHERITS`, and the `PARTITION OF` form are
+    /// not parsed yet.
+    ///
+    /// See <https://www.postgresql.org/docs/current/sql-createforeigntable.html>
+    pub fn parse_create_foreign_table(&mut self) -> Result<CreateForeignTable, ParserError> {
+        let if_not_exists = self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]);
+        let name = self.parse_object_name(false)?;
+        if self.peek_token_ref().token != Token::LParen {
+            return self.expected_ref(
+                "'(' before the column list of CREATE FOREIGN TABLE",
+                self.peek_token_ref(),
+            );
+        }
+        let (columns, constraints) = self.parse_columns()?;
+        self.expect_keyword_is(Keyword::SERVER)?;
+        let server_name = self.parse_identifier()?;
+        let options = self.parse_pg_options_clause()?;
+
+        Ok(CreateForeignTable {
+            name,
+            if_not_exists,
+            columns,
+            constraints,
+            server_name,
+            options,
+        })
+    }
+
     /// The index of the first unprocessed token.
     pub fn index(&self) -> usize {
         self.index

tests/sqlparser_postgres.rs

@@ -9639,6 +9639,102 @@ fn parse_lock_table() {
     }
 }
 
+#[test]
+fn parse_create_foreign_table() {
+    // Each of these round-trips through Display, so verified_stmt already pins
+    // the name, columns, server and IF NOT EXISTS. Only the parsed shape that
+    // Display cannot show is asserted below.
+    for sql in [
+        "CREATE FOREIGN TABLE ft1 (id INTEGER, name TEXT) SERVER myserver",
+        "CREATE FOREIGN TABLE IF NOT EXISTS ft2 (col INTEGER) SERVER remoteserver",
+    ] {
+        assert!(matches!(
+            pg_and_generic().verified_stmt(sql),
+            Statement::CreateForeignTable(_)
+        ));
+    }
+
+    let sql =
+        "CREATE FOREIGN TABLE ft3 (col INTEGER) SERVER remoteserver OPTIONS (schema_name 'public')";
+    let Statement::CreateForeignTable(stmt) = pg_and_generic().verified_stmt(sql) else {
+        unreachable!()
+    };
+    assert_eq!(
+        stmt.options,
+        Some(vec![CreateServerOption {
+            key: "schema_name".into(),
+            value: Ident {
+                value: "public".to_string(),
+                quote_style: Some('\''),
+                span: Span::empty(),
+            },
+        }])
+    );
+}
+
+#[test]
+fn parse_create_foreign_table_requires_column_list() {
+    // Without the parens Display would invent a `()` the input never had.
+    assert!(matches!(
+        pg_and_generic().parse_sql_statements("CREATE FOREIGN TABLE ft SERVER s"),
+        Err(ParserError::ParserError(_))
+    ));
+
+    // An empty list is still legal PostgreSQL.
+    pg_and_generic().verified_stmt("CREATE FOREIGN TABLE ft () SERVER s");
+}
+
+#[test]
+fn parse_create_foreign_table_rejects_modifiers() {
+    // None of these has a field on CreateForeignTable, so accepting one would
+    // drop it silently on the way back out through Display.
+    for sql in [
+        "CREATE TEMPORARY FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE GLOBAL FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE LOCAL FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE TRANSIENT FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE VOLATILE FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE OR ALTER FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE MULTISET FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE SET FOREIGN TABLE ft (a INT) SERVER s",
+        "CREATE ALGORITHM = UNDEFINED FOREIGN TABLE ft (a INT) SERVER s",
+    ] {
+        let err = pg_and_generic().parse_sql_statements(sql).unwrap_err();
+        assert!(
+            err.to_string()
+                .contains("CREATE FOREIGN TABLE does not accept this modifier"),
+            "unexpected error for {sql}: {err}"
+        );
+    }
+
+    // OR REPLACE is caught by an earlier arm, so it never reaches the guard.
+    assert!(matches!(
+        pg_and_generic()
+            .parse_sql_statements("CREATE OR REPLACE FOREIGN TABLE ft (a INT) SERVER s"),
+        Err(ParserError::ParserError(_))
+    ));
+}
+
+#[test]
+fn parse_create_foreign_table_with_check_constraint() {
+    // PostgreSQL accepts table-level CHECK constraints in CREATE FOREIGN TABLE.
+    let sql =
+        "CREATE FOREIGN TABLE ft (id INTEGER, CONSTRAINT id_positive CHECK (id > 0)) SERVER s";
+    let Statement::CreateForeignTable(stmt) = pg_and_generic().verified_stmt(sql) else {
+        unreachable!()
+    };
+    assert_eq!(stmt.columns.len(), 1);
+    assert_eq!(stmt.constraints.len(), 1);
+
+    // Zero columns with only a table-level constraint must not emit `(, CONSTRAINT ...)`.
+    let sql = "CREATE FOREIGN TABLE ft (CONSTRAINT c CHECK (id > 0)) SERVER s";
+    let Statement::CreateForeignTable(stmt) = pg_and_generic().verified_stmt(sql) else {
+        unreachable!()
+    };
+    assert_eq!(stmt.columns.len(), 0);
+    assert_eq!(stmt.constraints.len(), 1);
+}
+
 #[test]
 fn exclude_as_column_name() {
     // `EXCLUDE` is a non-reserved keyword, so it stays usable as a column name