&引用；“不为空”；未在mySQL中生成所需的结果

我正在尝试基于我的表构建一个报表。这是我的桌子：

下面是获得所需结果的SQL查询

SELECT
  `user`,
  SUM(
    CASE
      WHEN `event_time` >= '2021-04-01 00:00:00'
      AND `event_time` <= '2021-04-16 23:59:59'
      AND `sub_status` = 'TB'
      THEN pause_sec
    END
  ) AS 'Training Break',
  SUM(
    CASE
      WHEN `event_time` >= '2021-04-01 00:00:00'
      AND `event_time` <= '2021-04-16 23:59:59'
      AND `sub_status` = 'SB1'
      THEN pause_sec
    END
  ) AS 'Short Break 1',
  SUM(
    CASE
      WHEN `event_time` >= '2021-04-01 00:00:00'
      AND `event_time` <= '2021-04-16 23:59:59'
      AND `sub_status` = 'SB2'
      THEN pause_sec
    END
  ) AS 'Short Break 2',
  SUM(
    CASE
      WHEN `event_time` >= '2021-04-01 00:00:00'
      AND `event_time` <= '2021-04-16 23:59:59'
      AND `sub_status` = 'LB'
      THEN pause_sec
    END
  ) AS 'Long Break'
FROM
  `vicidial_agent_log`
GROUP BY `user`

---

请在此提供帮助或分享一篇有帮助的帖子。我一直在尝试查找，但不要对列名/别名使用单引号，因为例如

'Training Break'

在类似

'Training Break'的表达式中不为NULL

被解释为当然不为NULL的字符串文字。

在MySql中，可以使用倒勾来环绕列名。

此外，

Training Break

、

Short Break 1

、

Short Break 2

和

Long Break

列是聚合函数的结果，因此它们不能用于

WHERE

子句。改为使用

HAVING

子句。

最后，由于您希望这些列中至少有一列不为空的行，因此应使用运算符

或

，而不是

和

：

FROM
  `vicidial_agent_log`
GROUP BY `user`
HAVING `Training Break` IS NOT NULL
    OR `Short Break 1` IS NOT NULL
    OR `Short Break 2` IS NOT NULL
    OR `Long Break` IS NOT NULL

或：

---

首先，将

SUM（）

表达式的公共部分移动到

WHERE

子句中

第二，修正日期逻辑，这样你就不会错过一秒钟

我还强烈建议使用不需要转义的列名。因此：

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'
GROUP BY user;

SQL非常强大，可以让您在聚合之前或之后进行过滤。但是，通常在聚合之前进行过滤（从性能角度来看）要好得多

我还建议您使用不需要转义的标识符。而且，除了字符串和日期文字外，不要对任何内容使用单引号

FROM
  `vicidial_agent_log`
GROUP BY `user`
HAVING COALESCE(`Training Break`, `Short Break 1`, `Short Break 2`, `Long Break`) IS NOT NULL

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'
GROUP BY user;

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;