Question

mysql表：

table_results：

id  results

1   1 0 1 2 4 5
2   5 4 2 6  
3   7 2 8 2 4

我正在创建一个我需要的Yii gridview

SELECT SUM(results) AS results2 FROM table_results WHERE id = 1:

例如我必须对第一行求和：1 + 0 + 1 + 2 + 4 + 5并且作为results2 = 15。

如何在sql中做到这一点？

Answer 1

不需要动态SQL。您可以使用：

<强> SqlFiddleDemo

SELECT sub.id,  SUM(sub.val) AS `sum`
FROM
(
  SELECT id, SUBSTRING_INDEX(SUBSTRING_INDEX(t.results, ' ', n.n), ' ', -1) AS val
  FROM table_results t 
  CROSS JOIN 
  (
     SELECT a.N + b.N * 10 + 1 n
       FROM 
      (SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) a
     ,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) b
  ) n
  WHERE n.n <= 1 + (LENGTH(t.results) - LENGTH(REPLACE(t.results, ' ', '')))
) sub
-- WHERE sub.id = 1
GROUP BY sub.id

Answer 2

执行此操作的一种方法是使用动态SQL。所以，完全在MySQL中：

declare @sql varchar(2000);

select @sql = concat('select ', replace(results, ' ', '+'))
from table_results tr
where id = 1;

prepare s from @sql;
execute s;

deallocate prepare s;

作为注释：仅仅因为我回答了这个问题并不意味着我宽恕了数据结构。

SQL行列与数字之间的空格

2 个答案: