Question

这是我的测试表（仍然有更多列）。我刚刚在这里显示了一些专栏。

index   DateTime    Biomass Fossil Brown coal/Lignite   Fossil Coal-derived gas 
0   2/3/2018 23:00  4815    17359       192                 
1   2/3/2018 23:15  4811    17364       192 
2   2/3/2018 23:30  4801    17356       192

在这里，我想对每行总计（生物质，化石棕煤/褐煤，化石煤衍生的气体）。

我已经尝试过了。

select SUM([Biomass], [Fossil Brown coal/Lignite,Fossil Coal-derived gas])
From test
Where ID = '0'
Group by DateTime

但未获得预期的结果。预期结果将为（4815 + 17359 + 192 = 22366）

有人可以建议我哪里出了问题吗？

Answer 1

您似乎想要：

SELECT [DateTime], SUM(Biomass + [Fossil Brown coal/Lignite] + [Fossil Coal-derived gas])
FROM test t
WHERE ID = '0'
GROUP BY [DateTime];

编辑：您的错误提示为MySQL，因此您的查询为

SELECT `DateTime`, SUM(`Biomass` + `Fossil Brown coal/Lignite` + `Fossil Coal-derived gas`)
FROM `test` t
WHERE `ID` = '0'
GROUP BY `DateTime`;

Answer 2

当需要累加行而不是列时，可以使用SUM（）。

要对字段求和，只需使用运算符即可。

尝试以下代码：

SELECT ( Biomass + Fossil + Brown + Coal ) AS result FROM test WHERE ID = '0';

Answer 3

我认为这是您要实现的目标：

SELECT [DateTime],
    SUM(Biomass + 
    [Fossil Brown coal/Lignite] + 
    [Fossil Coal-derived gas]) AS MySum
FROM test
WHERE Index = 0
GROUP BY [DateTime]

仅供参考-您可能需要考虑将某些列重命名为不会过度使用特殊字符的东西。

编辑（对于MySQL）：

SELECT `DateTime`,
    SUM(Biomass + 
    `Fossil Brown coal/Lignite` + 
    `Fossil Coal-derived gas`) AS MySum
FROM test
WHERE Index = 0
GROUP BY `DateTime`

Answer 4

据我所知，

create table #temp([index] int identity(0,1),DateTime datetime,Biomass int,Fossil int,Brown int,[coal/Lignite] int
,[Fossil_Coal-derived] int,gas int)

select * from #temp

insert into #temp(DateTime,Biomass,Fossil,Brown,[coal/Lignite],[Fossil_Coal-derived],gas)
values('2/3/2018 23:30',4801,17356,589,1246,5200,192)

select SUM([Biomass]+[Fossil]+[Brown]+[coal/Lignite]+[Fossil_Coal-derived]+[gas]) total
From #temp
Where [index] = '0'
Group by DateTime

如何在SQL中按行分组？

4 个答案: