如果条件里面有mysql查询

Question

我需要在mysql查询中给出条件，

    select IF(r.name=NULL,'customer',r.name) as previlage 
 from users u LEFT JOIN role r on r.rid = u.uid ORDER BY u.created DESC\G

我需要检查if the r.name field is null then it should be displayed as customer，但现在if r.name is NULL then its displayed as null itself。我怎样才能做到这一点。谢谢。

Answer 1

您无法将NULL与=进行比较，您需要使用is null

r.name is null 

而不是

r.name=NULL

https://dev.mysql.com/doc/refman/5.0/en/working-with-null.html