Question

我在SQL Server中工作，我希望获得表中每个字符串的出现次数。为此，我写了以下查询：

declare @tag table (TagName nvarchar(255), total int)

insert into @tag 
    select Tagname, count(TagName) Total 
    from tblTrend 
    where DigTagValue = 1 
    group by Tagname

select * from @tag

返回的输出是：

TagName        Total
----------------------
P1Conv_Trip      1
P2Conv_Off       1
P2Conv_Trip      1
P3Conv_Off       1
Q1Conv_Off       1
Q2Conv_On        1
Q2Conv_Trip      1
Q3Conv_Off       2
Q3Conv_On        2
Q3Conv_Trip      1
W1Conv_Off       2
W1Conv_On        4
W1Conv_Trip      1
W2Conv_On        2
W2Conv_Trip      1
W3Conv_Off       1
W3Conv_On        1
W4Conv_Off       1
W4Conv_Trip      1
W5Conv_Off       1
W5Conv_On        2
W5Conv_Trip      1

但我想要的输出应该是这样的：

TagName    ON    OFF    TRIP
------------------------------
  P1       0      0      1 
  P2       0      1      1
  P3       0      1      0
  Q1       0      1      0
  Q2       1      0      1
  Q3       2      2      1
  W1       4      2      1          
  W2       2      0      1
  W3       1      1      0
  W4       0      1      1
  W5       2      1      1

如何实现此输出？

Answer 1

无需使用临时表。试试这个查询

select
    Tagname, [On] = count(case when suffix = 'On' then 1 end)
    , [Off] = count(case when suffix = 'Off' then 1 end)
    , [trip] = count(case when suffix = 'trip' then 1 end)
from (
    select 
        Tagname = left(Tagname, 2)
        , suffix = substring(Tagname, charindex('_', Tagname) + 1, 4)
    from 
        tblTrend
    where
        DigTagValue=1
) t
group by Tagname

Answer 2

试试这个（我只考虑你的部分数据，以显示逻辑:)）：

declare @x table(TagName varchar(30), Total int)
insert into @x values
('P1Conv_Trip',1),
('P2Conv_Off',1),
('P2Conv_Trip',1),
('P3Conv_Off',1),
('Q1Conv_Off',1),
('Q2Conv_On',1),
('Q2Conv_Trip',1),
('Q3Conv_Off',2),
('Q3Conv_On',2),
('Q3Conv_Trip',1)

select [Tag],
       MAX(case when [status] = 'On' then [total] else 0 end) [ON],
       MAX(case when [status] = 'Off' then [total] else 0 end) [OFF],
       MAX(case when [status] = 'Trip' then [total] else 0 end) [TRIP]
from (
select SUBSTRING(TagName, 1, 2) [Tag],
       SUBSTRING(TagName, 8, LEN(tagname)) [Status],
       Total
from @x
) a group by [Tag]

Answer 3

你也可以使用如下PIVOT：

;WITH T AS
(
    SELECT 
        LEFT(TagName,2) AS TagName,
        SUBSTRING(TagName,CHARINDEX('_',TagName,0)+1,LEN(TagName)) AS ActionName,
        Total
    FROM @tblTest
)

SELECT 
    TagName,
    SUM(ISNULL([On],0)) AS [ON],SUM(ISNULL([Off],0)) AS [Off],SUM(ISNULL([Trip],0)) AS Trip
FROM T
PIVOT (
    MAX(Total) FOR ActionName IN ([ON],[Off],[Trip])
) pvt
GROUP BY TagName

SQL Server：在表中获取每个字符串

3 个答案: