Added support for CREATE DOMAIN (#1830)

src/parser/mod.rs

@@ -4625,6 +4625,8 @@ impl<'a> Parser<'a> {
             self.parse_create_external_table(or_replace)
         } else if self.parse_keyword(Keyword::FUNCTION) {
             self.parse_create_function(or_alter, or_replace, temporary)
+        } else if self.parse_keyword(Keyword::DOMAIN) {
+            self.parse_create_domain()
         } else if self.parse_keyword(Keyword::TRIGGER) {
             self.parse_create_trigger(or_alter, or_replace, false)
         } else if self.parse_keywords(&[Keyword::CONSTRAINT, Keyword::TRIGGER]) {
@@ -5974,6 +5976,35 @@ impl<'a> Parser<'a> {
         Ok(owner)
     }
 
+    /// Parses a [Statement::CreateDomain] statement.
+    fn parse_create_domain(&mut self) -> Result<Statement, ParserError> {
+        let name = self.parse_object_name(false)?;
+        self.expect_keyword_is(Keyword::AS)?;
+        let data_type = self.parse_data_type()?;
+        let collation = if self.parse_keyword(Keyword::COLLATE) {
+            Some(self.parse_identifier()?)
+        } else {
+            None
+        };
+        let default = if self.parse_keyword(Keyword::DEFAULT) {
+            Some(self.parse_expr()?)
+        } else {
+            None
+        };
+        let mut constraints = Vec::new();
+        while let Some(constraint) = self.parse_optional_table_constraint()? {
+            constraints.push(constraint);
+        }
+
+        Ok(Statement::CreateDomain(CreateDomain {
+            name,
+            data_type,
+            collation,
+            default,
+            constraints,
+        }))
+    }
+
     /// ```sql
     ///     CREATE POLICY name ON table_name [ AS { PERMISSIVE | RESTRICTIVE } ]
     ///     [ FOR { ALL | SELECT | INSERT | UPDATE | DELETE } ]