MERGE INTO semicolon handling (#508)

* SGA-4181 MERGE INTO semicolon handling

* fixed lint warning

Co-authored-by: Maciej Skrzypkowski <maciej.skrzypkowski@satoricyber.com>

src/parser.rs

@@ -4250,7 +4250,7 @@ impl<'a> Parser<'a> {
     pub fn parse_merge_clauses(&mut self) -> Result<Vec<MergeClause>, ParserError> {
         let mut clauses: Vec<MergeClause> = vec![];
         loop {
-            if self.peek_token() == Token::EOF {
+            if self.peek_token() == Token::EOF || self.peek_token() == Token::SemiColon {
                 break;
             }
             self.expect_keyword(Keyword::WHEN)?;

tests/sqlparser_common.rs

@@ -4574,6 +4574,21 @@ fn test_merge_into_using_table() {
     verified_stmt(sql);
 }
 
+#[test]
+fn test_merge_with_delimiter() {
+    let sql = "MERGE INTO target_table USING source_table \
+    ON target_table.id = source_table.oooid \
+    WHEN MATCHED THEN \
+        UPDATE SET target_table.description = source_table.description \
+    WHEN NOT MATCHED THEN \
+        INSERT (ID, description) VALUES (source_table.id, source_table.description);";
+
+    match parse_sql_statements(sql) {
+        Ok(_) => {}
+        _ => unreachable!(),
+    }
+}
+
 #[test]
 fn test_lock() {
     let sql = "SELECT * FROM student WHERE id = '1' FOR UPDATE";