使用 mysql 查询每 3 个计数行分组

Question

can anyone help me to group every 3 counts rows??? I have data like this

num	score
1	3
1	3
1	3
1	3
1	3
1	3
4	3
4	3
4	3
2	3
2	3
2	3

and i want result like this

num	count(num)
1	3
1	3
2	3
4	3

Answer 1

Please read terms & condition for asking in Stackoverflow. Your question can't be understood!

Answer 2

You want to group every 3 rows. But without giving supplementary conditions, we can only take assumptions on how you would like to group. Supposing each row in the 3-rows group has the same content and the score value from the base table has no influence on grouping, I guess you just want to get the num once for every 3 rows as the 3 rows have the same num. Besides, we use a constant value 3 for count(num) column. If all my assumptions come true, try this:

select num, 3 as 'count(num)' 
from (select num,@row_id:=@row_id+1 as row_id 
     from test,(select @row_id:=0) t1 ) t2
where row_id mod 3 =0
order by num
;