oacle select返回一个空值

select '' internal_number, ... from test
Array
(
    [0] => Array
        (
            [INTERNAL_NUMBER] => 
            [SECID] => BMW0508370
            [RECEIVEDATE] => 2010-02-21
            [SUPPLIER_NAME] => 佛山市珅宝汽车销售服务有限公司
            [STATUS] => P
            [DATA_ENTER_PERSON] => 
            [SERVICE_TOTAL] => 0
            [REAL_COST] => 300
            [TOLLFEE] => 
        )
        ...