使用Where like对同一列进行多次计数 - MySQL

Question

我正在尝试使用不同的 where like 子句对同一列进行多次计数。

我已经弄清楚了每个类似子句的基本查询，但我需要将它们组合起来以产生一个结果。

select system_user, COUNT(details) from asset_log where details like 'Viewed';
select system_user, COUNT(details) from asset_log where details like 'Viewed Web%';
select system_user, COUNT(details) from asset_log where details like 'ThumbView';
select system_user, COUNT(details) from asset_log where details like 'Exported%';

我确信这是可能的，我只是不知道该怎么做。任何帮助将不胜感激。

提前感谢

更新：

这最终对我有用，

select distinct system_user, 
    SUM(CASE WHEN details ='viewed' then 1 Else 0 end) AS viewed_count,
    SUM(CASE WHEN details Like 'Viewed Web%' then 1 Else 0 end) AS Web_count,
    SUM(CASE WHEN details = 'ThumbView' then 1 Else 0 end) AS ThumbView_count,
    SUM(CASE WHEN details Like 'Exported%' then 1 Else 0 end) AS Exported_count
from asset_log GROUP BY system_user; 

谢谢！

Answer 1

您可以使用 SUM/Case 来“旋转”计数

select system_user, 

    SUM(CASE WHEN details ='viewed' then 1 Else 0 end) viewed_count
    SUM(CASE WHEN details Like 'Viewed Web%' then 1 Else 0 end) Viewed Web_count
    SUM(CASE WHEN details = 'ThumbView' then 1 Else 0 end) ThumbView_count
    SUM(CASE WHEN details Like 'Exported%' then 1 Else 0 end) Exported_count
from asset_log 
where 
    details = 'viewed' or
    details like 'Viewed Web%' or
    details = 'ThumbView' or
    details like 'Exported%' 
 group by 
      system_user

注意：如果没有通配符，我不会费心使用“Like”

Answer 2

您可以使用 SUM/CASE 组合来实现所需的结果，如答案 https://stackoverflow.com/a/8870028/ 625594。

对于您的情况，确切的查询将是：

select system_user, 
SUM(CASE WHEN details like 'Viewed' THEN 1 ELSE 0) AS `sum1`,  
SUM(CASE WHEN details like 'Viewed Web%' THEN 1 ELSE 0) AS `sum2`,
SUM(CASE WHEN details like 'ThumbView' THEN 1 ELSE 0) AS `sum3`,
SUM(CASE WHEN details like 'Exported%' THEN 1 ELSE 0) AS `sum4`
from asset_log;

Answer 3

你可以这样写：

SELECT MAX(system_user) AS system_user, COUNT(*)
  FROM asset_log
  WHERE details = 'Viewed'
  OR details like 'Viewed Web%'
  OR details = 'ThumbView'
  OR details like 'Exported%'

由于 system_user 大概都是相同的，MAX() 只会随机得到一个，它解决了无法将聚合列与非聚合列组合起来。