Mysql 在when-case中使用sum函数

如何在每种情况下不计算一个值，如何计算一次并在每种情况下使用

将计数移动到子查询，并将大小写移动到外部，如下图所示：

SELECT  '2017-05-30' AS `short_date`,
        'Stats' AS `group`,
        'Active ' AS `subgroup`,
         '' AS `row`,
         CASE
WHEN COUNT(DISTINCT(guild_name)) >= 1 AND  COUNT(DISTINCT(guild_name)) <= 5   THEN '1 - 5 ' 
WHEN COUNT(DISTINCT(guild_name)) >= 6 AND COUNT(DISTINCT(guild_name)) <= 10  THEN '6 - 10 '
WHEN COUNT(DISTINCT(guild_name)) >= 11 AND COUNT(DISTINCT(guild_name)) <= 15 THEN '11 - 15 '
WHEN COUNT(DISTINCT(guild_name)) >= 16 AND COUNT(DISTINCT(guild_name)) <= 20 THEN '16 - 20 '
WHEN COUNT(DISTINCT(guild_name)) >= 21 AND COUNT(DISTINCT(guild_name)) <= 25 THEN '21 - 25 '
WHEN COUNT(DISTINCT(guild_name)) >= 30 THEN '> 30' END AS `value`
FROM  table
WHERE guild_name !=0
GROUP BY
                `short_date`,
                `group`,
                `subgroup`

---

这样，在子查询中只执行一次计数，而外部查询对结果集进行处理

将计数移动到子查询，并将大小写移动到外部，如下图所示：

SELECT  '2017-05-30' AS `short_date`,
        'Stats' AS `group`,
        'Active ' AS `subgroup`,
         '' AS `row`,
         CASE
WHEN COUNT(DISTINCT(guild_name)) >= 1 AND  COUNT(DISTINCT(guild_name)) <= 5   THEN '1 - 5 ' 
WHEN COUNT(DISTINCT(guild_name)) >= 6 AND COUNT(DISTINCT(guild_name)) <= 10  THEN '6 - 10 '
WHEN COUNT(DISTINCT(guild_name)) >= 11 AND COUNT(DISTINCT(guild_name)) <= 15 THEN '11 - 15 '
WHEN COUNT(DISTINCT(guild_name)) >= 16 AND COUNT(DISTINCT(guild_name)) <= 20 THEN '16 - 20 '
WHEN COUNT(DISTINCT(guild_name)) >= 21 AND COUNT(DISTINCT(guild_name)) <= 25 THEN '21 - 25 '
WHEN COUNT(DISTINCT(guild_name)) >= 30 THEN '> 30' END AS `value`
FROM  table
WHERE guild_name !=0
GROUP BY
                `short_date`,
                `group`,
                `subgroup`

---

这样，在子查询中只执行一次计数，而外部查询对结果集进行处理

您的问题看起来像是在为三个分组字段输入字符串？此查询将返回一行，其中包含不同的帮会名称。您是否打算稍后扩展此功能以针对多个短日期、组和子组运行？@ScottieB是的，我知道您的问题看起来像是在为三个分组字段输入字符串？此查询将返回一行，其中包含不同的帮会名称。您是否打算稍后扩展此功能，以针对多个短日期、组和子组运行？@ScottieB是的，我有