code: protected SqlSource buildSqlSourceFromStrings(String[] strings,
  			Class<?> parameterTypeClass) {
  		final StringBuilder sql = new StringBuilder();
  		for (String fragment : strings) {
  			sql.append(fragment);
  			sql.append(" ");
  		}
  		LanguageDriver languageDriver = getLanguageDriver();
  		return languageDriver.createSqlSource(configuration, sql.toString().trim(),
  				parameterTypeClass);
  	}
docs: build sql source for mybatis from string concat by array.