select c.sid,sum(case when 功能 = 1 then 1 else 0 end ) as '开通1号功能的人数',
sum(case when 功能 = 2 then 1 else 0 end ) as '开通2号功能的人数',
count(s.sid) as '登录人数'
from city c
left join student s on c.sid= s.sid
group by c.sid

------解决方案--------------------

SELECT 城市表.Ssdm Sid,
      COUNT(学生表.Sname) Stu_Num,
      SUM(CASE
              WHEN 字段开通1号 THEN 1 ELSE 0
            END) A1_Num,
      SUM(CASE
              WHEN  字段开通2号 THEN 1 ELSE 0
            END) A2_Num,
      COUNT(学生表.Loginnum) Log_Num
 FROM 学生表, 城市表
  WHERE 城市表.Ssdm = 学生表.Ssdm
  GROUP BY 城市表.Ssdm