Question

我有一个名为“Users”的字段，我想在该字段上运行SUM（），返回所有DISTINCT记录的总和。我认为这样可行：

SELECT SUM(DISTINCT table_name.users)
FROM table_name

但是它没有选择DISTINCT记录，它只是运行就好像我运行了SUM（table_name.users）。

如果只添加此字段中的不同记录，我该怎么做？

Answer 1

此代码似乎表示sum（distinct）和sum（）返回不同的值。

with t as (
select 1 as a 
union all
select '1'
union all
select '2'
union all
select '4'
)

select sum(distinct a) as DistinctSum, sum(a) as allSum, count(distinct a) as distinctCount, count(a) as allCount from t

你真的有非独特的价值吗？

select count(1), users
from table_name
group by users
having count(1) > 1

如果没有，总和将是相同的。

Answer 2

使用count()

SELECT count(DISTINCT table_name.users)
FROM table_name

SQLFiddle demo

Answer 3

您可以通过以下示例自行查看不同的作品。在这里，我创建一个具有重复值的子查询，然后我对这些值做一个不同的总和。

select DistinctSum=sum(distinct x), RegularSum=Sum(x)
from
(

    select x=1
    union All
    select 1
    union All
    select 2
    union All
    select 2

) x

您可以看到，此示例中，distinct sum列返回3，常规sum返回6。

Answer 4

您可以使用子查询：

select sum(users)
from (select distinct users from table_name);

Answer 5

;WITH cte
as
  (
  SELECT table_name.users , rn = ROW_NUMBER() OVER (PARTITION BY users  ORDER BY users) 
          FROM table_name
  )
SELECT SUM(users)
FROM cte 
WHERE rn = 1

SQL Fiddle

自己尝试一下的 TEST

DECLARE @table_name Table (Users INT ); INSERT INTO @table_name Values (1),(1),(1),(3),(3),(5),(5); ;WITH cte as ( SELECT users , rn = ROW_NUMBER() OVER (PARTITION BY users ORDER BY users) FROM @table_name ) SELECT SUM(users) DisSum FROM cte WHERE rn = 1

<强>结果

DisSum 9

Answer 6

SUM(DISTINCTROW table_name.something)

它对我有用（innodb）。

说明 - ＆＃34; DISTINCTROW根据整个重复记录省略数据，而不仅仅是重复的字段。＆＃34; http://office.microsoft.com/en-001/access-help/all-distinct-distinctrow-top-predicates-HA001231351.aspx

Answer 7

如果情况很难在sum子句中编织一个“ distinct”，通常可以在整个查询中添加一个额外的“ where”子句-类似于：

select sum(t.ColToSum)
from SomeTable t
where (select count(*) from SomeTable t1 where t1.ColToSum = t.ColToSum and t1.ID < t.ID) = 0

Answer 8

可能与 Trying to sum distinct values SQL

根据Declan_K's answer：

首先获取不重复列表...

SELECT SUM(SQ.COST)
FROM 
(SELECT DISTINCT [Tracking #] as TRACK,[Ship Cost] as COST FROM YourTable) SQ

用于DISTINCT记录的SQL Server SUM（）

8 个答案:

SQLFiddle demo