mysql group中能否使用两个count呢

Answer 1

In fact, it is best to describe your table structure. The following answer is based on the limited information you provided:

select district as 行政区
，count(1) as 小区数 -- 我默认你每个小区时一条记录，且无重复
, sum(if(idNB = 1 ,1 ,0)) as 高档小区数 -- 假设高档小区的idNB标记为1
from table_name 
group by district

其实 sum(if(idNB = 1 ,1 ,0)) 也可以替换成count(idNB = 1 or null)

Answer 2

mysql does not support analytic functions:

select t1.district, 
    (select count(t2.xiaoqu) from table t2 where t2.district=t1.district) count_xiaoqu,
    (select count(t2.idNB) from table t2 where t2.district=t1.district) count_idNB
from table t1

How to write analysis function:

select district, 
count(xiaoqu) over (district) count_xiaoqu, 
count(idNB) over (district) count_idNB
from table

Answer 3

Let me tell you my thoughts here. Use MySQL to count the high-end communities and non-high-end communities in the area

select district,idNB,count(*) from xx GROUP BY district,idNB

Then the total number of cells in the area is processed and calculated by the server itself.