Question

MySql查询问题：

作为sql的新手，我有以下问题。我不得不将4个查询合并为一个用于报告软件。代码正在运行，但结果不是我想要的。

尝试使用UNION语句，显示计数但所有排序均在1＆＃39; count（*）＆＃39;领域。

我希望每个查询中都有4个字段（总报警，已确认总数，15分钟内确认总数，15分钟后确认总数）

到目前为止，这是我的代码：

select
  count(*) 'Total alarms'
 FROM  alarminfo
 where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0'))

union 

select
 count(ack_time) 'Total Acknowledged'
 FROM  alarminfo
  where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0')

 )

union 

select
   count(*) 'Total acknowledged within 15min'
 FROM  alarminfo
  where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0') AND
    (TIMESTAMPDIFF(SECOND,alarminfo.set_time ,alarminfo.ack_time)<60*15))

union 

select
   count(*) 'Total acknowledged after 15min'
 FROM  alarminfo
  where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0') AND
    (TIMESTAMPDIFF(SECOND,alarminfo.set_time ,alarminfo.ack_time)>60*15))

任何人都知道如何在单独的字段下对每个计数进行排序？

Answer 1

我认为你需要条件聚合。例如

select
  count(*) 'Total alarms',
  sum(case when ack_time is not null then 1 else 0 end) as 'total acknowledged',
  sum(case when (TIMESTAMPDIFF(SECOND,alarminfo.set_time ,alarminfo.ack_time)<60*15) then 1 else 0 end) as 'Total acknowledged within 15min',
  sum(case when (TIMESTAMPDIFF(SECOND,alarminfo.set_time ,alarminfo.ack_time)>60*15) then 1 else 0 end) as 'Total acknowledged after 15min'
 FROM  alarminfo
 where
 alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0'

Answer 2

首先，您需要在所有联合查询中使用相同的列名。

其次，如果你想要所有人都是同一个名字，那么你应该使用＆＃34; UNION ALL＆＃34;如果结果有重复的记录。

在你的情况下，你可以这样做：

select
  count(*) AS 'count', 'Total alarms' As 'label' 
 FROM  alarminfo
 where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0'))

union 

select
 count(ack_time) AS 'count', 'Total Acknowledged' As 'label'
 FROM  alarminfo
  where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0')

 )

union 

select
   count(*) AS 'count', 'Total acknowledged within 15min' AS 'label'
 FROM  alarminfo
  where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0') AND
    (TIMESTAMPDIFF(SECOND,alarminfo.set_time ,alarminfo.ack_time)<60*15))

union 

select
   count(*) AS 'count',  'Total acknowledged after 15min' AS 'label'
 FROM  alarminfo
  where
 ((alarminfo.set_time>='2017-09-01 00:00:00.0' AND alarminfo.set_time<'2017-09-15 23:59:59.0') AND
    (TIMESTAMPDIFF(SECOND,alarminfo.set_time ,alarminfo.ack_time)>60*15))

结合多个选择查询问题

2 个答案: