NVL成效出不来 结果还都是null

SELECT   DISTINCT NVL(LM_LICENSE.LICENSE_TYPE_ID,0),
                                          NVL(CASE_MASTER.CASE_ID,0),
                                          NVL(CASE_PRODUCT.PRODUCT_ID,0),
                                          NVL(CASE_PRODUCT.SEQ_NUM,0)
                          FROM   CASE_MASTER,
                                 CASE_PRODUCT,
                                 LM_PRODUCT,
                                 LM_LIC_PRODUCTS,
                                 LM_LICENSE
                         WHERE   CASE_MASTER.CASE_ID = CASE_PRODUCT.CASE_ID
                                 AND CASE_PRODUCT.PRODUCT_ID =
                                       LM_PRODUCT.PRODUCT_ID
                                 AND LM_PRODUCT.PRODUCT_ID =
                                       LM_LIC_PRODUCTS.PRODUCT_ID
                                 AND LM_LIC_PRODUCTS.LICENSE_ID =
                                       LM_LICENSE.LICENSE_ID
                                 AND CASE_MASTER.DELETED IS NULL
                                 AND CASE_PRODUCT.DELETED IS NULL
                                 AND LM_PRODUCT.DELETED IS NULL
                                 AND LM_LIC_PRODUCTS.DELETED IS NULL
                                 AND LM_LICENSE.DELETED IS NULL
                                 AND LM_LICENSE.COUNTRY_ID = 107
                                 AND CASE_MASTER.COUNTRY_ID = 107
                                 AND CASE_PRODUCT.PROTOCOL_FOLLOWED IS NULL
                                 AND CASE_PRODUCT.PRODUCT_ID IS NOT NULL
                                 AND CASE_MASTER.CASE_ID = 15415412