Question

我有一个看起来像这样的表：

CREATE TABLE [dbo].[Phrase] 
(
    [PhraseId]     UNIQUEIDENTIFIER DEFAULT (newid()) NOT NULL,
    [English]      NVARCHAR (250)   NOT NULL,
    [p1]           BIT              DEFAULT ((0)) NOT NULL,
    [p2]           BIT              DEFAULT ((0)) NOT NULL,
    [p3]           BIT              DEFAULT ((0)) NOT NULL, 

    PRIMARY KEY CLUSTERED ([PhraseId] ASC),

    CONSTRAINT [FK_PhrasePhraseChapter] 
        FOREIGN KEY ([ChapterId]) 
        REFERENCES [dbo].[PhraseChapter] ([PhraseChapterShortId])
);

我想要做的是得到p1，p2和p3的计数，所以输出看起来像：

p1  100
p2  200
p3  23

请注意，在这种情况下，第一行意味着Phrase表中有100行将p1设置为值1.希望这是有道理的。

我知道我可以使用三列简单地执行此操作，但我需要一个只有两个字符串列的行输出，如上所述。任何人都可以给我一个关于如何实现这个目标的建议吗？

Answer 1

使用联盟：

select 'P1' as ColToCount,
       count(distinct P1) as Counted
from MyTable
where 1=1 -- replace with any criteria
union all
select 'P2' as ColToCount,
       count(distinct P2) as Counted
from MyTable
where 1=1 -- replace with any criteria
union all
select 'P3' as ColToCount,
       count(distinct P3) as Counted
from MyTable
where 1=1 -- replace with any criteria

如果你只有几件不同的东西可以计算，这真的很好

Answer 2

您可以使用UNPIVOT，如下所示：

SELECT  myColumn ,
        NoOfTrue
FROM    ( SELECT    [p1] = COUNT(CASE WHEN [p1] = 1 THEN 1 END) ,
                    [p2] = COUNT(CASE WHEN [p2] = 1 THEN 1 END) ,
                    [p3] = COUNT(CASE WHEN [p3] = 1 THEN 1 END)
          FROM      Phrase
        ) d UNPIVOT
    ( NoOfTrue FOR myColumn IN ( [p1], [p2], [p3] ) ) piv;

Answer 3

也许通过使用案例和总和：

SELECT sum(case when p1 = 1 then 1 end) as p1Count, 
       sum(case when p2 = 1 then 1 end) as p2Count,
       sum(case when p3 = 1 then 1 end) as p3Count
FROM Phrase

Answer 4

最简单的方法是：

select 'p1' p, sum(p1) countp
from Phrase
union all
select 'p2', sum(p2)
from Phrase
union all
select 'p3', sum(p3)
from Phrase;

注意sum字段使用bit可以完成您想要的所有操作 bit字段可以包含（0 - 1 - null）个值，sum会将null值添加为0;

如何计算查询中的多个列，每个列的行数为一行？

4 个答案: