如何从SQL中的datetime中删除时间

这是我的查询：

select date(datetime) as dates,
        user_id,
        sum(CASE When status='completed' Then 1 Else 0 End ) as completed,
        sum(CASE When status='incompleted' Then 1 Else 0 End ) as incompleted,
        sum(CASE When status!='' Then 1 Else 0 End ) as total 
from routine_streak 
where user_id ='"+user_id+"' 
and datetime  between '"+start+"' and '"+end+"' 
group by user_id,date(datetime)

它将提供如下输出：

"datetime": "2019-01-30T00:00:00.000Z

不过我希望这样：

"datetime": "2019-01-30"

使用如下所示的查询

<?php 
var str = "select DATE_FORMAT(datetime,'%y-%m-%d') as dates,from routine_streak where user_id='183' group by user_id)"; 
?>