标签:Count 1990 experiment ifnull experiments platform Experiments name
题目描述:
Write an SQL query to report the number of experiments done on each of the three platforms for each of the three given experiments. Notice that all the pairs of (platform, experiment) should be included in the output including the pairs with zero experiments.
Return the result table in any order.
The query result format is in the following example.
Example 1:
方法1:
主要思路:解题链接汇总
select 'Android' as platform, 'Reading' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'Android' and experiment_name ='Reading'
union all select 'Android' as platform, 'Sports' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'Android' and experiment_name ='Sports'
union all select 'Android' as platform, 'Programming' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'Android' and experiment_name ='Programming'
union all select 'IOS' as platform, 'Reading' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'IOS' and experiment_name ='Reading'
union all select 'IOS' as platform, 'Sports' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'IOS' and experiment_name ='Sports'
union all select 'IOS' as platform, 'Programming' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'IOS' and experiment_name ='Programming'
union all select 'Web' as platform, 'Reading' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'Web' and experiment_name ='Reading'
union all select 'Web' as platform, 'Sports' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'Web' and experiment_name ='Sports'
union all select 'Web' as platform, 'Programming' as experiment_name,ifnull(count(*),0) as num_experiments
from Experiments
where platform = 'Web' and experiment_name ='Programming'
标签:Count,1990,experiment,ifnull,experiments,platform,Experiments,name 来源: https://blog.csdn.net/weixin_44171872/article/details/120112226
本站声明: 1. iCode9 技术分享网(下文简称本站)提供的所有内容,仅供技术学习、探讨和分享; 2. 关于本站的所有留言、评论、转载及引用,纯属内容发起人的个人观点,与本站观点和立场无关; 3. 关于本站的所有言论和文字,纯属内容发起人的个人观点,与本站观点和立场无关; 4. 本站文章均是网友提供,不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属;如您发现该文章侵犯了您的权益,可联系我们第一时间进行删除; 5. 本站为非盈利性的个人网站,所有内容不会用来进行牟利,也不会利用任何形式的广告来间接获益,纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。