PostgreSQL: Support NATIONAL CHAR

src/ast/data_type.rs

@@ -104,6 +104,10 @@ pub enum DataType {
     ///
     /// [SQL Standard]: https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html#national-character-string-type
     NationalCharacterVarying(Option<CharacterLength>),
+    /// National char type, e.g. NATIONAL CHAR(10), [SQL Standard].
+    ///
+    /// [SQL Standard]: https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html#national-character-string-type
+    NationalChar(Option<CharacterLength>),
     /// Uuid type.
     Uuid,
     /// Large character object with optional length,
@@ -557,6 +561,7 @@ impl fmt::Display for DataType {
             DataType::NationalCharacterVarying(size) => {
                 format_character_string_type(f, "NATIONAL CHARACTER VARYING", size)
             }
+            DataType::NationalChar(size) => format_character_string_type(f, "NATIONAL CHAR", size),
             DataType::Uuid => write!(f, "UUID"),
             DataType::CharacterLargeObject(size) => {
                 format_type_with_optional_length(f, "CHARACTER LARGE OBJECT", size, false)

src/parser/mod.rs

@@ -13865,6 +13865,12 @@ impl<'a> Parser<'a> {
                         ))
                     }
                 }
+                Keyword::NATIONAL if self.peek_keyword(Keyword::CHAR) => {
+                    let _ = self.parse_keyword(Keyword::CHAR);
+                    Ok(DataType::NationalChar(
+                        self.parse_optional_character_length()?,
+                    ))
+                }
                 Keyword::CLOB => Ok(DataType::Clob(self.parse_optional_precision()?)),
                 Keyword::BINARY => Ok(DataType::Binary(self.parse_optional_precision()?)),
                 Keyword::VARBINARY => Ok(DataType::Varbinary(self.parse_optional_binary_length()?)),
@@ -23076,6 +23082,8 @@ mod tests {
                 "NATIONAL CHARACTER VARYING(20)",
                 DataType::NationalCharacterVarying(length)
             );
+            test_parse_data_type!(dialect, "NATIONAL CHAR", DataType::NationalChar(None));
+            test_parse_data_type!(dialect, "NATIONAL CHAR(20)", DataType::NationalChar(length));
         }
 
         #[test]

tests/sqlparser_common.rs

@@ -23490,6 +23490,8 @@ fn parse_national_character_string_types() {
         "NATIONAL CHARACTER(4)",
         "NATIONAL CHARACTER VARYING",
         "NATIONAL CHARACTER VARYING(4)",
+        "NATIONAL CHAR",
+        "NATIONAL CHAR(4)",
     ] {
         dialects.verified_stmt(&format!("CREATE TABLE t (c {data_type})"));
         dialects.verified_expr(&format!("CAST('ab' AS {data_type})"));