错误代码：1054：当表存在时，'字段列表'中的未知列'table_name.column_name'

Question

我正在尝试运行 mySQL 查询以从我的数据库中获取数据。以下是我的查询：

SELECT user,
      SUM(CASE WHEN sub_status = 'TB' THEN pause_sec END) AS Training_Break,
      SUM(CASE WHEN sub_status = 'SB1' THEN pause_sec END) AS Short_Break_1,
      SUM(CASE WHEN sub_status = 'SB2' THEN pause_sec END) AS Short_Break_2,
      SUM(CASE WHEN sub_status = 'LB' THEN pause_sec END) AS Long_Break
FROM vicidial_agent_log
WHERE event_time >= '2021-04-01' AND
      event_time < '2021-04-17' AND
      sub_status IN ('TB', 'SB1', 'SB2', 'LB')
GROUP BY user
HAVING COALESCE(`Training Break`, `Short Break 1`, `Short Break 2`, `Long Break`) IS NOT NULL

这会产生预期的结果： Table Output on the results. 我想显示用户的姓名，但他们在另一个表中。所以，我在这里使用 join 如下：

SELECT `vicidial_agent_log.user`,
`vicidial_users.full_name`,
      SUM(CASE WHEN `vicidial_agent_log.sub_status` = 'TB' THEN `vicidial_agent_log.pause_sec` END) AS Training_Break,
      SUM(CASE WHEN `vicidial_agent_log.sub_status` = 'SB1' THEN `vicidial_agent_log.pause_sec` END) AS Short_Break_1,
      SUM(CASE WHEN `vicidial_agent_log.sub_status` = 'SB2' THEN `vicidial_agent_log.pause_sec` END) AS Short_Break_2,
      SUM(CASE WHEN `vicidial_agent_log.sub_status` = 'LB' THEN `vicidial_agent_log.pause_sec` END) AS Long_Break
FROM `vicidial_agent_log`
INNER JOIN `vicidial_users` ON `vicidial_users.user`=`vicidial_agent_log.user`
WHERE `vicidial_agent_log.event_time` >= '2021-04-01' AND
      `vicidial_agent_log.event_time` < '2021-04-17' AND
      `vicidial_agent_log.sub_status` IN ('TB', 'SB1', 'SB2', 'LB')
GROUP BY `vicidial_agent_log.user`
HAVING COALESCE(`Training_Break`, `Short_Break_1`, `Short_Break_2`, `Long_Break`) IS NOT NULL

它会产生以下错误：

错误代码：1054 Unknown column 'vicidial_agent_log.user' in 'field list'

但是表存在。
另外，如果我删除代码中的反引号，它会生成此错误：

错误代码：1054 Unknown column 'vicidial_agent_log.user' in 'group statement'

以下是我的两个表及其列的字段：
>vicidial_agent_log 的列：[agent_log_id, user, ...]
>vicidial_users 的列：[user_id, user, pass, full_name, ...]

我想要的输出应该看起来像 https://i.stack.imgur.com/GVeIz.png 只是添加了一个带有名称的列。


这是我的第一个专业项目正在建设中，任何形式的帮助都可以。我一定犯了一个可能很小的初学者错误。我不确定我的逻辑或概念是否有问题。我研究了其他帖子，但它似乎对我不起作用。任何形式的帮助都会大有帮助。

Answer 1

不要逃避你的标识符！并使用别名！我想我在之前的回答中提到了这一点。所以：

SELECT al.user, u.full_name,
      SUM(CASE WHEN al.sub_status = 'TB' THEN al.pause_sec  END) AS Training_Break,
      SUM(CASE WHEN al.sub_status = 'SB1' THEN al.pause_sec END) AS Short_Break_1,
      SUM(CASE WHEN al.sub_status = 'SB2' THEN al.pause_sec END) AS Short_Break_2,
      SUM(CASE WHEN al.sub_status = 'LB' THEN al.pause_sec END) AS Long_Break
FROM vicidial_agent_log al JOIN
     vicidial_users u
     ON u.user = al.user
WHERE al.event_time >= '2021-04-01' AND
      al.event_time < '2021-04-17' AND
      al.sub_status IN ('TB', 'SB1', 'SB2', 'LB')
GROUP BY al.user, u.full_name;

此版本不需要HAVING 子句，除非al.pause_sec 可以是NULL。如果可能，只需将al.pause_sec IS NOT NULL 添加到WHERE 子句。

您的查询的问题在于

`vicidial_agent_log.user`

指的是其中包含. 的列名。你打算：

`vicidial_agent_log`.`user`

但是当反引号相当于：

vicidial_agent_log.user

或者：

al.user

当表别名被定义时。