我有一个插入命令如下

Insert into table1 (host, ip, domain ) 
    select hostname, (case when t1.ip is null then 'Not Defined' end) , domain from table1 t1, table2 t2 
    where t1.status = "Done"
    and t2.statusnew not regexp "True"
    limit 10 ;

获取错误： ip cannot be null