我可以在Mysql中的两列之间求和吗？

Question

我想做的是以下内容：

SELECT SUM(ABS(`number_x` - `number_y`)) AS `total_difference` FROM `table`

表格如下：

  

id | number_x |编号y

     

1 | 4 | 2

     

2 | 3 | 2

     

3 | 2 | 4

所以答案应该是： （4-2 = 2）+（3-2 = 1）+（2-4 = 2）= 5

我可以在MySQL中执行此操作吗？

谢谢！

Answer 1

您发布的查询应该没有问题：

SELECT SUM(ABS(`number_x` - `number_y`)) AS `total_difference` 
FROM `table`

或者如果你想用这样的子查询来编写它：

SELECT SUM(diff) AS `total_difference` 
FROM
( 
    SELECT Id, ABS(number_x - number_y) diff
    FROM TableName
) t

Answer 2

SELECT SUM(ABS(`number_x` - `number_y`)) AS `total_difference` FROM `table`

或者你可以用别的方式写，但我更喜欢上面的

SELECT ABS(SUM(number_x) - SUM(number_y)) AS total_difference FROM table