将具有不同 WHERE 子句的多个 SELECT 语句的结果组合到一个查询中

Question

我有一个 table，其中有一列有 15 个不同的名称 (TotalName)，其中两个名称是 flowOne 和 flowTwo。还有一列是时间戳 (t_stamp) 和值。每次将新值添加到 table 时，它都会加上时间戳以及它的来源。我正在尝试创建一个查询，该查询将为我提供 15 个不同名称中的每一个的列以及月份的总数和月份编号。我已经尝试了其中两个名称，但它们最终出现在不同的行中。我想让它在一个月内全部显示在同一行。

SELECT  YEAR(t_stamp) as 'Year', MONTH(t_stamp) as 'Month', sum(FlowTotals.FlowTotal) as 'flowOne', '' as 'flowTwo'
FROM DataBase.dbo.FlowTotals
WHERE FlowTotals.TotalName = 'flowOne'
    and year(t_stamp) = year(getDate())
Group By Year(t_stamp), Month(t_stamp)

UNION

SELECT  YEAR(t_stamp) as 'Year', MONTH(t_stamp) as 'Month', '' as 'flowOne', sum(FlowTotals.FlowTotal) as 'flowTwo'
FROM DataBase.dbo.FlowTotals
WHERE FlowTotals.TotalName = 'flowTwo'
    and year(t_stamp) = year(getDate())
Group By Year(t_stamp), Month(t_stamp)

按月排序

这样就出来了

Year   Month   totalOne   totalTwo
2019     1     123456     0
2019     1     0          789123
2019     2     456789     0
2019     2     0          345678

我希望第 1 个月有一行，第 2 个月有一行，该行的所有值等等。

我知道部分问题是我的 Select 语句中有 '' 作为 'flowOne，但这是我能想到的分成 2 个不同列的唯一方法。每行的总和按预期工作。

Answer 1

而不是 union 你的两个查询，join 它们在 q1.year = q2.year and q1.month = q2.month。

Answer 2

一种简单的方法并且对您的查询几乎没有改变，将您的 select 包装为一个 cte，然后将此 cte 用于 group by year 和 month并得到 sum(FlowOne) 和 sum(FlowTwo)，像这样（我用 0 替换了空字符串，所以总和有效，因为它们都是数字。转换只是为了防止 SQL 在内部转换它是 bit 而不是 int:

with cte as(
SELECT  YEAR(t_stamp) as 'Year', MONTH(t_stamp) as 'Month', sum(FlowTotals.FlowTotal) as 'flowOne', cast(0 as int) as 'flowTwo'
FROM DataBase.dbo.FlowTotals
WHERE FlowTotals.TotalName = 'flowOne'
    and year(t_stamp) = year(getDate())
Group By Year(t_stamp), Month(t_stamp)
UNION
SELECT  YEAR(t_stamp) as 'Year', MONTH(t_stamp) as 'Month', cast(0 as int) as 'flowOne', sum(FlowTotals.FlowTotal) as 'flowTwo'
FROM DataBase.dbo.FlowTotals
WHERE FlowTotals.TotalName = 'flowTwo'
  and year(t_stamp) = year(getDate())
Group By Year(t_stamp), Month(t_stamp)
)
select c.Year, c.Month, sum(c.FlowOne), sum(c.FlowTwo)
from cte as c
group by c.Year, c.Month

将具有不同 WHERE 子句的多个 SELECT 语句的结果组合到一个查询中

Combining results from multiple SELECT statements with different WHERE clauses into one query

sql-server

sql-server-2008

sql-server-2008-r2