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按累计列金额限制

limit sql mysql

Guy Louzon · 技术社区 · 7 年前

假设我有一个有3列的表: id,行类型,行分数

我想选择第一(或最新)行,但根据获取的id的累积分数限制选择

例子 table

id | row_type | row_score
 1          a                  1
 2          a                  1
 3          b                  2
 4          c                  3
 5          a                  1
 6          b                  2
 7          a                  1
...

第一行成绩,累计得分限制为4分:

id | row_type | row_score
 1          a                  1
 2          a                  1
 3          b                  2

2 回复 | 直到 7 年前

Nick SamSmith1986 7 年前

此查询应该满足您的要求。它使用一个变量来保存一个累积分数,然后在 HAVING 子句来限制返回的行:

SELECT t1.*, @cum_score := @cum_score + row_score AS cum_score
FROM table1 t1
JOIN (SELECT @cum_score := 0) c
HAVING cum_score <= 4
ORDER BY cum_score

输出:

id  row_type    row_score   cum_score
1   a           1           1
2   a           1           2
3   b           2           4

SQLFiddle Demo

Rohan Hodarkar 7 年前

select t1.id, t1.row_type,t1.row_score, SUM(t2.row_score) as sum
from table t1
inner join table t2 
on t1.id >= t2.id
group by t1.id, t1.row_type,t1.row_score
having SUM(t2.row_score)<=4
order by t1.id

谢谢,