请高人把sql 性能 效率 优化下。。谢谢。。分全送。。
下面的city_id in(....) 这里数据是不同的，所以要多个sql union all 在一起，
比如sqlA如下：根据city_id 的范围不同还会有 同样的sql 需要union all 在一起。。求优化。
- SQL code
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------解决方案--------------------------------------------------------
可以试下minus~ 来代替in或者是not in
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需要了解更多的问题：
1、 你这个语句，a、b、c 三张表是直接 笛卡尔 连接（无连接条件）？
2、 a、b、c 三张表所选择出来的数据行大约有多少行？
3、 city_id in ('001','002','003') 里面的值大约有多少个？
两个稍微复杂点的问题：
1、 ${tableName} 索引是怎么建的？
2 、这个SQL的执行计划是怎么样的？
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我是来看看我的等级的！！！
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楼主应该发到数据库栏目中，那里数据库高手比较多。
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用in的效率都是非常低的哈，最好不要用in 可以考虑数据库的设计，或者其他函数来实现，
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首先，a b c 3个表没有关联条件，那就是3个表交叉组合
其次，a b c 3个表的检索相似，没有必要特意写成3个表，直接和在一个就可以了
- SQL code
select 'city_name' = '写死的', 'fixed_net' = sum(case certify_user_type when 1 then 1 else 0 end ) , 'school_net' = sum(case certify_user_type when 3 then 1 else 0 end ), 'differ_net' = sum(case certify_user_type when 4 then 1 else 0 end ), 'wlan_net' = sum(case certify_user_type when 5 then 1 else 0 end ), 'other_net' = sum(case certify_user_type when 0 then 1 else 0 end ), 'oneType_user' = sum(case when user_type_id=1 and certify_user_type<>2 then 1 else 0 end ) , 'twoType_user' = sum(case when user_type_id=2 and certify_user_type<>2 then b.num else 0 end ), 'threeType_user' = sum(case when user_type_id=3 and certify_user_type<>2 then 1 else 0 end ), 'other_user' = sum(case when user_type_id=99 and certify_user_type<>2 then 1 else 0 end ), 'local_rom' = sum(case romflag when 0 then 1 else 0 end ), 'out_rom' = sum(case romflag when 1 then 1 else 0 end ), 'in_rom' = sum(case romflag when 2 then 1 else 0 end ), 'nation_out_rom' = sum(case romflag when 3 then 1 else 0 end ), 'nation_in_rom' = sum(case romflag when 5 then 1 else 0 end ) from ${tableName} where city_id in ('001','002','003') --你的动态条件