MySql 1046报错求解

这是老师的代码：

这是我的代码：

SELECT city,count(1) FROM date.dateanalyst
group by city
having count(if(industryField like "%电子商务%",1,null))>= 50
;

数据库错字没关系。

但是一直报错1046：

Error Code: 1046. No database selected
 Select the default DB to be used by double-clicking its name in the SCHEMAS list in the sidebar.    0.000 sec