blocks|key|1997327|text|如果id不是字符串，则不应该引用这些值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1997328|SELECT+SUM(A+%2B+B+%2B+C)+as+"subtotal"+FROM+alphabet+WHERE+id+IN+(1,5,378);|code-block|syntax|javascript|1997329|这是可行的，但可能会有一个不明显的后果。如果任何行都具有A+not+null，而其他一行为null，则该行将退出求和，因为null加任何其他内容都为null，而SUM运算符忽略了null。因此，更安全的做法是：|1997330|SELECT+SUM(A)+%2B+SUM(B)+%2B+SUM(C)+as+"subtotal"+FROM+alphabet+WHERE+id+IN+(1,5,378);|1997331|这也存在同样的潜在问题，但不太可能发生，因为整个列必须为null。如果你仍然关心这个问题，有各种方言的具体方法来防御这个问题。最便携的是痛苦而冗长的：|1997332|SELECT+SUM(
++++++CASE
++++++++WHEN+A+IS+NULL
++++++++THEN+0
++++++++ELSE+A
++++++END
++++++%2B
++++++CASE
++++++++WHEN+B+IS+NULL
++++++++THEN+0
++++++++ELSE+B
++++++END
++++++%2B
++++++CASE
++++++++WHEN+c+IS+NULL
++++++++THEN+0
++++++++ELSE+C
++++++END
++++)+as+"subtotal"
FROM+alphabet
WHERE+id+IN+(1,5,378);|1997333|entityMap^0|2|2|0|0|S|1|28|3|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|14|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|T|$]]

If <code>id</code> is not a string, you shouldn't quote those values.

<pre><code>SELECT SUM(A + B + C) as "subtotal" FROM alphabet WHERE id IN (1,5,378);
</code></pre>

This should work, but may may have one non-obvious consequence. If any row has <code>A</code> not null and one of the others null, that row will drop out of the summation because a null plus anything else is null, and nulls are ignored by the <code>SUM</code> operator. Thus it may be safer to write:

<pre><code>SELECT SUM(A) + SUM(B) + SUM(C) as "subtotal" FROM alphabet WHERE id IN (1,5,378);
</code></pre>

This suffers from the same potential problem, but it is less likely to happen because an entire column would have to be null. There are various dialect specific ways to defend against that problem if you are still concerned. The most portable is the painfully verbose:

<pre><code>SELECT SUM(
 CASE
 WHEN A IS NULL
 THEN 0
 ELSE A
 END
 +
 CASE
 WHEN B IS NULL
 THEN 0
 ELSE B
 END
 +
 CASE
 WHEN c IS NULL
 THEN 0
 ELSE C
 END
 ) as "subtotal"
FROM alphabet
WHERE id IN (1,5,378);
</code></pre>

blocks|key|1997337|text|declare+
++++@a+int+=+0,+
++++@b+int+=+5,
++++@c+int+=+NULL

select+
++++ISNULL(@a,+0)+%2B+ISNULL(@b,+0)+%2B+ISNULL(@c,+0)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1997338|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>declare 
 @a int = 0, 
 @b int = 5,
 @c int = NULL

select 
 ISNULL(@a, 0) + ISNULL(@b, 0) + ISNULL(@c, 0)
</code></pre>

I know this question might seem a little basic stuff but I want to make sure I get the right syntax because this line of code will run often:

I want to sum columns A, B and C of table "alphabet" for all rows which have an id included in my IN clause.

This is how I would do it but I'd like a confirmation if possible:

<pre><code>SELECT SUM(A + B + C) as "subtotal" FROM alphabet WHERE id IN ('1','5','378');
</code></pre>

SQL sum of 3 columns

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我知道这个问题似乎有点基础，但我想确保我的语法是正确的，因为这一行代码将经常运行：对于包含在我的in子句中的所有行，我想对表“字母表”的A、B和C列进行求和。我就是这样做的，但如果可能的话，我想确认一下：SELECT SUM(A + B + C) as "subtotal" FROM alphabet WHERE id...

问3列的SQL和
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问3列的SQL和EN