drop table 报错

SELECT * FROM All_Tables WHERE table_name = 'F_Material_QUALITY_EXAMINATION'能看到表 存在 ZZ 用户的select * from "F_Material_QUALITY_EXAMINATION"  也行 
但是 DROP TABLE f_material_quality_examination就报错ORA-00942: 表或视图不存在
下面是 建表语句
declare
  a NUMBER;
BEGIN
  select count(1)
  into a
  from user_tables
  where table_name = 'F_Material_QUALITY_EXAMINATION';
  if a > 0 then
  dbms_output.put_line('F_Material_QUALITY_EXAMINATION表存在');
  else
  dbms_output.put_line('F_Material_QUALITY_EXAMINATION表不存在');
  EXECUTE IMMEDIATE '
create table "F_Material_QUALITY_EXAMINATION"   
(
  QUALITY_N_ID VARCHAR2(32) not null,
  SUPPLIER_CODE VARCHAR2(32),
  BRAND_CODE VARCHAR2(32),
  PRODUCT_DEPARTMENT_CODE VARCHAR2(32),
  REPORT_DATE_CODE VARCHAR2(8),
  GJZJL VARCHAR2(255),
  SGZBX VARCHAR2(255),
  GYSGJX VARCHAR2(255),
  QUALIFIED_PERCENT NUMBER(14,2),
  UNQUALIFIED_PERCENT NUMBER(14,2),
  COMPROMISE_PERCENT NUMBER(14,2),
  CHECKOUT_RESULT VARCHAR2(255),
  constraint PK_F_MATERIAL_QUALITY_EXAMINAT primary key (QUALITY_N_ID)
)
partition by range(QUALITY_N_ID)(
partition P2010
values less than (''20100401-20110331'')
)';
  EXECUTE IMMEDIATE '
comment on table "F_Material_QUALITY_EXAMINATION" is
''sdf ''';
  EXECUTE IMMEDIATE '
comment on column "F_Material_QUALITY_EXAMINATION".SUPPLIER_CODE is
''sdfsf''';
   
  END if;
END;麻烦看看谢谢