Oracle使用NVL()函数问题

Question

Oracle 语句如下

SELECT tuihuitime,kaibiaoremark,danweiguid,danweiname,rowguid,biaoduanguid from PingBiao_KaibiaoTouBiao WHERE  
BiaoDuanGuid='83a78c4c-eeab-4073-865b-9bb7f88916b2' and IsTouBiao='1' 
and IsSucceed='1' 

当使用NVL()函数添加对字段 tuihuitime 的判断后，得到的查询结果却变成了空

and (nvl(tuihuitime,'')='')

Answer 1

nvl一般是给一个非空的值，你这个(tuihuitime,'') 最终不还是返回null么，那你条件就应该是

and (nvl(tuihuitime,'') is null)