Question

我有一个我感兴趣的两列的表格。

一列是日期，另一列是标记名。

我想将标记名返回到与同一日期匹配的不同列中。

我可以使用子查询来实现这一点，但有更有效的方法吗？我正在谈论检索大约20-30k行，这导致大约300,000个查询

选择插入的最有效方法是什么，以确保日期相互排列。

这是我目前的询问。（我需要每个标记名的值在行中排成一行）

谢谢

SELECT ah1.DateTime,ah1.Value as TPH,
(select value
from dbo.AnalogHistory
where tagname = 'LS_EM1_NXG.NXG_I'
and datetime = ah1.DateTime
) as EM1_Current,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM2_NXG.NXG_I'
and datetime = ah1.DateTime
) as EM2_Current,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM1_NXG.NXG_SPEED'
and datetime = ah1.DateTime
) as EM1_Speed,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM2_NXG.NXG_SPEED'
and datetime = ah1.DateTime
) as EM2_Speed,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM1_NXG.NXG_P'
and datetime = ah1.DateTime
) as EM1_Power,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM2_NXG.NXG_P'
and datetime = ah1.DateTime
) as EM2_Power,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM1_NXG.NXG_TRQ'
and datetime = ah1.DateTime
) as EM1_Torque,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM2_NXG.NXG_TRQ'
and datetime = ah1.DateTime
) as EM2_Torque,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM1_NXG.NXG_TRQ_UTIL'
and datetime = ah1.DateTime
) as EM1_Torque_U,

(select value
from dbo.AnalogHistory
where tagname = 'LS_EM2_NXG.NXG_TRQ_UTIL'
and datetime = ah1.DateTime
) as EM2_Torque_U,

(select value
from dbo.AnalogHistory
where tagname = 'LS_TE754001G.PVAI'
and datetime = ah1.DateTime
) as EM1_NDE,

(select value
from dbo.AnalogHistory
where tagname = 'LS_TE754001H.PVAI'
and datetime = ah1.DateTime
) as EM1_DE

  FROM [Runtime].[dbo].[AnalogHistory] ah1
  where TagName = 'CR_WQI752010.PVAI'
  and wwResolution = '600000'
  and DateTime > '20160816'
  and wwRetrievalMode = 'cyclic'

Answer 1

也许您可以使用条件聚合。像这样：

select datetime,
       max(case when tagname = 'LS_EM1_NXG.NXG_I' then value end) as val1,
       . . .
from dbo.AnalogHistory
group by datetime ;

Answer 2

您可以使用下面的CASE ..

    select 
    case when tagname = 'LS_EM1_NXG.NXG_I'
    and datetime = ah1.DateTime then value end as em1
    --do for all tags
    from
    table
    FROM [Runtime].[dbo].[AnalogHistory] ah1
   where  wwResolution = '600000'
   and DateTime > '20160816'
  and wwRetrievalMode = 'cyclic'

Answer 3

SELECT 
 date(datetime) as d,
(select 
      group_concat(tagname)
    from
      dbo.AnalogHistory
    where
        date(datetime) = d
        group by date(datetime))as res
FROM
 dbo.AnalogHistory
 group by date(datetime);

Answer 4

我认为你想要UNPIVOT或PIVOT。见worked UNPIVOT/PIVOT examples

将SQL数据从单个列返回到多个列

4 个答案: