select 城市,出现次数= count(1) from table group by 城市
城市 出现次数 北京 12 上海 5 ... ... select 城市 ,count(1)as 出现次数 from t group by 城市
select 城市,count(*) as 出现次数 from 表 group by 城市 order by 出现次数 desc
select 城市,count(*) as 出现次数 from 表 group by 城市 order by count(*) desc
select 城市,sum(出现次数) as 出现次数 from 表名 group by 城市