Support BEGIN as standalon clause (#17)

* Support BEGIN as standalon clause

* Only affect snowflake logic

Author: Vedin

src/dialect/snowflake.rs

@@ -132,7 +132,24 @@ impl Dialect for SnowflakeDialect {
 
     fn parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
         if parser.parse_keyword(Keyword::BEGIN) {
-            return Some(parser.parse_begin_exception_end());
+            // Allow standalone BEGIN; for Snowflake
+            match &parser.peek_token_ref().token {
+                Token::SemiColon | Token::EOF => {
+                    return Some(Ok(Statement::StartTransaction {
+                        modes: Default::default(),
+                        begin: true,
+                        transaction: None,
+                        modifier: None,
+                        statements: vec![],
+                        exception: None,
+                        has_end_keyword: false,
+                    }))
+                }
+                _ => {
+                    // BEGIN ... [EXCEPTION] ... END block
+                    return Some(parser.parse_begin_exception_end());
+                }
+            }
         }
 
         if parser.parse_keywords(&[Keyword::ALTER, Keyword::SESSION]) {

tests/sqlparser_snowflake.rs

@@ -4343,6 +4343,40 @@ fn test_snowflake_fetch_clause_syntax() {
     );
 }
 
+#[test]
+fn test_snowflake_begin_standalone() {
+    // BEGIN; (no END) should be allowed for Snowflake
+    let mut stmts = snowflake().parse_sql_statements("BEGIN;").unwrap();
+    assert_eq!(1, stmts.len());
+    match stmts.remove(0) {
+        Statement::StartTransaction {
+            begin,
+            has_end_keyword,
+            statements,
+            ..
+        } => {
+            assert!(begin);
+            assert!(!has_end_keyword);
+            assert!(statements.is_empty());
+        }
+        other => panic!("unexpected stmt: {other:?}"),
+    }
+}
+
+#[test]
+fn test_snowflake_begin_commit_sequence() {
+    let mut stmts = snowflake().parse_sql_statements("BEGIN; COMMIT;").unwrap();
+    assert_eq!(2, stmts.len());
+    match stmts.remove(0) {
+        Statement::StartTransaction { begin, .. } => assert!(begin),
+        other => panic!("unexpected first stmt: {other:?}"),
+    }
+    match stmts.remove(0) {
+        Statement::Commit { end, .. } => assert!(!end),
+        other => panic!("unexpected second stmt: {other:?}"),
+    }
+}
+
 #[test]
 fn test_snowflake_create_view_with_multiple_column_options() {
     let create_view_with_tag =