@Override
    public List<String> getDuplicateKeyUpdate() {
        return null;
    }
@Test
    public void testGetDuplicateKeyUpdate() {
        String sql = "insert into t(a) values (?)";
        SQLStatement ast = getSQLStatement(sql);

        SqlServerInsertRecognizer recognizer = new SqlServerInsertRecognizer(sql, ast);
        Assertions.assertNull(recognizer.getDuplicateKeyUpdate());
    }