PostgreSQL: Parse NCHAR as a character string type

src/ast/data_type.rs

@@ -112,6 +112,10 @@ pub enum DataType {
     ///
     /// [SQL Standard]: https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html#national-character-string-type
     NationalCharVarying(Option<CharacterLength>),
+    /// National char type, e.g. NCHAR(10), [SQL Standard].
+    ///
+    /// [SQL Standard]: https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html#national-character-string-type
+    Nchar(Option<CharacterLength>),
     /// Uuid type.
     Uuid,
     /// Large character object with optional length,
@@ -569,6 +573,7 @@ impl fmt::Display for DataType {
             DataType::NationalCharVarying(size) => {
                 format_character_string_type(f, "NATIONAL CHAR VARYING", size)
             }
+            DataType::Nchar(size) => format_character_string_type(f, "NCHAR", size),
             DataType::Uuid => write!(f, "UUID"),
             DataType::CharacterLargeObject(size) => {
                 format_type_with_optional_length(f, "CHARACTER LARGE OBJECT", size, false)

src/parser/mod.rs

@@ -13877,6 +13877,7 @@ impl<'a> Parser<'a> {
                         ))
                     }
                 }
+                Keyword::NCHAR => Ok(DataType::Nchar(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()?)),
@@ -23095,6 +23096,8 @@ mod tests {
                 "NATIONAL CHAR VARYING(20)",
                 DataType::NationalCharVarying(length)
             );
+            test_parse_data_type!(dialect, "NCHAR", DataType::Nchar(None));
+            test_parse_data_type!(dialect, "NCHAR(20)", DataType::Nchar(length));
         }
 
         #[test]

tests/sqlparser_common.rs

@@ -23493,6 +23493,8 @@ fn parse_national_character_string_types() {
         "NATIONAL CHAR",
         "NATIONAL CHAR(4)",
         "NATIONAL CHAR VARYING(4)",
+        "NCHAR",
+        "NCHAR(4)",
     ] {
         dialects.verified_stmt(&format!("CREATE TABLE t (c {data_type})"));
         dialects.verified_expr(&format!("CAST('ab' AS {data_type})"));