sql 语句的优化有关问题。

select aa.fixed_net,aa.school_net,aa.differ_net,aa.wlan_net,aa.other_net,aa.city_name,aa.oneType_user,aa.twoType_user,aa.threeType_user,aa.other_user,aa.local_rom,aa.out_rom,aa.in_rom ,aa.nation_out_rom,aa.nation_in_rom from (select     'city_name' = '写死的',     'fixed_net' = sum(case a.id when 1 then a.num else 0 end ) ,    'school_net' = sum(case a.id when 3 then a.num else 0 end ),    'differ_net' = sum(case a.id when 4 then a.num else 0 end ),    'wlan_net' = sum(case a.id when 5 then a.num else 0 end ),    'other_net' = sum(case a.id when 0 then a.num else 0 end ),    'oneType_user' = sum(case b.id when 1 then b.num else 0 end ) ,    'twoType_user' = sum(case b.id when 2 then b.num else 0 end ),    'threeType_user' = sum(case b.id when 3 then b.num else 0 end ),    'other_user' = sum(case b.id when 99 then b.num else 0 end ),    'local_rom' = sum(case c.id when 0 then c.num else 0 end ),    'out_rom' = sum(case c.id when 1 then c.num else 0 end ),    'in_rom' = sum(case c.id when 2 then c.num else 0 end ),    'nation_out_rom' = sum(case c.id when 3 then c.num else 0 end ),    'nation_in_rom' = sum(case c.id when 5 then c.num else 0 end )     from      (select count(user_id) as num,certify_user_type as id         from ${tableName} where certify_user_type not in (2) and city_id in ('001','002','003') //此处的数据是动态的        group by certify_user_type    ) a     ,       ( select count(user_id) as num ,user_type_id as id         from ${tableName}         where user_type_id in (1,2,3,99) and certify_user_type=2 and city_id in ('001','002','003')         group by user_type_id    ) b     ,     ( select count(user_id) as num,romflag as id         from ${tableName} where city_id in ('001','002','003')         group by romflag    ) c) aa