如何在同一个查询中添加两个选择命令的结果

How to add results of two select commands in same query(如何在同一个查询中添加两个选择命令的结果)

问题描述

我目前有两个选择命令，如下所示.我想要做的是将结果添加到 SQL 查询中，而不是代码中的变量.

I currently have two select commands as per below. What I would like to do is to add the results together in the SQL query rather than the variables in code.

select sum(hours) from resource;
select sum(hours) from projects-time;

是否可以在同一个 SQL 中同时输出两个结果的总和?

Is it possible to have both in the same SQL and output a sum of both results?

推荐答案

是的.可能 :D

SELECT  SUM(totalHours) totalHours
FROM
        ( 
            select sum(hours) totalHours from resource
            UNION ALL
            select sum(hours) totalHours from projects-time
        ) s

作为旁注，必须对表名 projects-time 进行分隔以避免语法错误.分隔符因您使用的 RDBMS 而异.

As a sidenote, the tablename projects-time must be delimited to avoid syntax error. Delimiter symbols vary on RDBMS you are using.

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