Question

我有一个非常大的以下查询：

SELECT 
    DATE(added_on) 'Week Of', 
    COUNT(*) 'No. Updates', 
    (CASE WHEN COUNT(*) <= 500 THEN 6.75 WHEN COUNT(*) <= 750 
      THEN 6.30 WHEN COUNT(*) <= 1000 THEN 6.00 WHEN COUNT(*) <= 1250 
      THEN 5.50 ELSE 4.60 END
     ) Rate
    Rate * COUNT(*) // HOW TO DO THIS??
FROM
     Fox_title
GROUP BY
    WEEK(added_on)
ORDER BY
    added_on

我如何将COUNT(*) *我Rate语句中的CASE多个？或者我是否必须再次编写CASE语句？

Answer 1

重复case或使用子查询：

select t.*, t.Rate * `No. Updates`
from (SELECT DATE(min(added_on)) as `Week Of`, COUNT(*) as `No. Updates`, 
             (CASE WHEN COUNT(*) <= 500 THEN 6.75
                   WHEN COUNT(*) <= 750 THEN 6.30
                   WHEN COUNT(*) <= 1000 THEN 6.00
                   WHEN COUNT(*) <= 1250 THEN 5.50
                   ELSE 4.60
              END) as Rate
      FROM Fox_title
      GROUP BY WEEK(added_on)
     ) t
ORDER BY `Week Of`;

我对您的查询进行了一些其他更改。首先，我将列别名周围的单引号更改为后退标记。通常，单引号应仅用于字符串常量。 Back ticks是用于封装标识符的MySQL方法。

我还将date(addon)更改为date(min(addon))。这可确保您获得本周最早的日期。否则，你会得到一个任意的日期。

mysql使用CASE STATEMENT作为变量

1 个答案: