Question

我需要一些关于Android应用中的SUM功能的帮助。我有一个类似于以下内容的表：

我需要SUM最后两个记录之间的数量Notes和最后一个记录与Note。我需要将行数31,32和33相加。它将返回90.我已经尝试了

SELECT Sum(QUANTITY) FROM fuel_table WHERE NOTE!='' ORDER BY ID DESC

但它会返回带有注释的所有数量的SUM。

Answer 1

WITH    max_id_with_note AS
        (
        SELECT  MAX(ID) AS max_id
        FROM    YourTable
        WHERE   IFNULL(note, '') <> ''
        )
,       previous_max_id_with_note AS
        (
        SELECT  max(ID) as max_id
        FROM    YourTable
        WHERE   IFNULL(note, '') <> ''
                AND ID < (SELECT max_id FROM max_id_with_note)
        )
SELECT  SUM(Quantity)
FROM    YourTable
WHERE   (SELECT max_id FROM previous_max_id_with_note)
        < ID and ID <= 
        (SELECT max_id FROM max_id_with_note)

Example at SQL Fiddle.

Answer 2

我倾向于将这个问题说成：将所有具有一个音符的行的数量相加＆＃34;提前＆＃34;他们这表明：

select sum(quantity)
from (select ft.*,
             (select count(*)
              from fuel_table ft2
              where ft2.note = 'Yes' and ft2.id >= ft.id
             ) as numNotesAhead
      from fuel_table ft
     ) ft
where numNotesAhead = 1;

Answer 3

首先选择几个ROW并从此选择查询SUM（）。在你的情况下它看起来像这样：

Select SUM(t1.QUANTITY) FROM (SELECT QUANTITY from fuel_table WHERE NOTE!='' ORDER BY ID limit 2) as t1

Answer 4

将您的查询更改为

SELECT Sum(QUANTITY) FROM fuel_table ORDER BY ID DESC LIMIT 3

Answer 5

使用sub query按QUANTITY和ID排除最后3行的LIMIT 3，并将SUM()添加到结果数量中。 ..

SELECT SUM(QUANTITY) FROM (SELECT QUANTITY FROM fuel_table ORDER BY ID DESC LIMIT 3);

Answer 6

我创建了一个像你一样的表并进行测试。 Andomar有个好主意，但没有犯错！

WITH    max_id_with_note AS
        (
        SELECT  MAX(ID) AS max_id
        FROM    fuel_table
        WHERE   Note <> ''
        )
,       previous_max_id_with_note AS
        (
        SELECT  max(ID) as max_id
        FROM    fuel_table
        WHERE   Note <> ''
                AND ID < (SELECT max_id FROM max_id_with_note)
        )
SELECT  SUM(Quantity)
FROM    fuel_table
WHERE          (SELECT max_id FROM previous_max_id_with_note)
        < id and id <= (SELECT max_id FROM max_id_with_note)

几行之间的SQLite SUM（）

6 个答案: