oracle中判断记录是否存在

为了避免全表扫描, 应该这样写:
Sql代码

1. select spu_id  
2.   from tbcat2.spu  
3. where category_id = #value#  
4.    and (status = 0 or status is null)  
5.    and rownum < 2  

select spu_id from tbcat2.spu where category_id = #value# and (status = 0 or status is null) and rownum < 2

而不是实用count(*)函数, 对于海量数据全表扫描性能是极差的