MySQL-如何创建自动对行求和的列? [英] Mysql - How to create column that automatically sums rows?

问题描述

我有一个名为"character"的mysql数据库表，其中包含名称，力量，智力，技能等列.我想创建一个自动总结实力，才智和技能的专栏.这可能吗?

I have a mysql database table called "character" with columns like name, strength, intelligence, skill. I want to create a column that sums up strength, intelligence and skill AUTOMATICALLY. Is this possible?

我看到了许多页面，这些页面显示了如何进行查询.我做了一个查询就好了，例如 从字符中选择(str + intel + skl)作为总和； 它返回的总和就很好.

I have seen loads of pages showing how to do queries. I did a query just fine, such as select (str+intel+skl) as sum from character; It returns a sum just fine.

但是我想念(不明白)的是如何:

But what I'm missing (don't understand) is how to:

1. 要么将该查询自动执行到我的mysql数据库中(例如，当我从字符中选择*"时，它将显示强度，智力，技能，总和")，
2. 在何处/如何将mysql查询合并到我的rails应用中，以便SUM实时显示，以及何时进行编辑，例如强度发生时，SUM会相应更新.

关键是我要对一行中的各列求和(强度，智力，技能)，而不是对某列求和(几个字符的强度).

A key point, I am summing columns across a row (strength, intelligence, skill), not summing a column (strengths of several characters).

推荐答案

如果我正确理解了您的问题，并且力量，智力和技能列为数字数据类型，则此方法应该有效.

This should work, if I'm understanding your question correctly and the strength, intelligence, skill columns are numeric data types.

select strength, intelligence, skill, strength+intelligence+skill as sum
from character

如建议的那样，可以很容易地使用以下方法创建视图:

As suggested, a view could then be created pretty easily with:

create view totals as
select strength, intelligence, skill, strength+intelligence+skill as sum
from character

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