选择每行和下一行的SUM

Question

表三列id，numers1和number2。我们需要总结numers1和number2，但第一行到第二行numers1 numers2第二行有第三行和第三行等等。

CREATE TABLE tb1 (id INTEGER PRIMARY KEY AUTOINCREMENT,numbers1,numbers2);
INSERT INTO tb1 (numbers1,numbers2) values(1,10);
INSERT INTO tb1 (numbers1,numbers2) values(2,20);
INSERT INTO tb1 (numbers1,numbers2) values(3,30);
INSERT INTO tb1 (numbers1,numbers2) values(4,40);
INSERT INTO tb1 (numbers1,numbers2) values(5,50);

我想得到：

21
32
43
54

Answer 1

在此处获取每条记录的正确行索引的引用： How to use ROW_NUMBER in sqlite

我能够使用以下查询创建所需的结果：

SELECT
num1 + coalesce(b_num2, 0)
FROM(
SELECT 
num1,
(select count(*) from test as b  where a.id >= b.id)  as cnt
FROM test as a) as a
LEFT JOIN 
(SELECT num2 as b_num2, 
(select count(*) from test as b  where a.id >= b.id)  as cnt
 FROM test as a 
) as b
ON b.cnt = a.cnt + 1

说明：

通过连接两个相似记录索引的相同表，然后将下一条记录与当前记录合并，然后将当前记录的num1与下一条记录的num2相加，我不知道你想如何处理最后一行，因为它没有下一行所以我假设它没有添加任何只有num1

的值的结果

结果：

Answer 2

对于具有特定ID x的一行，您可以通过搜索大于x的ID值并获取第一行来获取下一行中的值：

SELECT ...
FROM tb1
WHERE id > x
ORDER BY id
LIMIT 1;

然后，您可以将其用作correlated subquery来获取每一行的值：

SELECT numbers1 + (SELECT T2.numbers2
                   FROM tb1 AS T2
                   WHERE T2.id > T1.id
                   ORDER BY T2.id
                   LIMIT 1) AS sum
FROM tb1 AS T1
WHERE sum IS NOT NULL;  -- this omits the last row, where the subquery returns NULL