select content,max(time) as max_time,count(1) as u

from 

(select  * 

,row_number() over(partition by content order by time asc) m1

,row_number() over(order by time asc) m2

 from test

) m group by content,m2-m1 HAVING count(1)>=3

__________

SELECT content,MAX(TIME) TIME,COUNT(content) contents

FROM test

GROUP BY content

HAVING COUNT(content) >= 3