“您尝试执行不包含指定的聚合函数的查询" [英] "You tried to execute a query that does not include the specified aggregate function"

问题描述

SELECT SUM(orders.quantity) AS num, fName, surname
FROM author
INNER JOIN book ON author.aID = book.authorID;

我不断收到错误消息:您试图执行不包含指定表达式"fName"的查询作为聚合函数的一部分.我该怎么办?

I keep getting the error message: "you tried to execute a query that does not include the specified expression "fName" as part of an aggregate function. What do I do?

推荐答案

该错误是因为fName包含在SELECT列表中，但没有包含在GROUP BY子句中，并且不是聚合的一部分功能(Count()，Min()，Max()，Sum()等)

The error is because fName is included in the SELECT list, but is not included in a GROUP BY clause and is not part of an aggregate function (Count(), Min(), Max(), Sum(), etc.)

您可以通过在GROUP BY中包含fName来解决该问题.但是，您将在surname上遇到同样的问题.因此，将它们都放在GROUP BY:

You can fix that problem by including fName in a GROUP BY. But then you will face the same issue with surname. So put both in the GROUP BY:

SELECT
    fName,
    surname,
    Count(*) AS num_rows
FROM
    author
    INNER JOIN book
    ON author.aID = book.authorID;
GROUP BY
    fName,
    surname

请注意，我在需要SUM(orders.quantity)的地方使用了Count(*).但是，orders未包含在查询的FROM部分中，因此必须先将其包括在内，然后才能Sum()它的一个字段.

Note I used Count(*) where you wanted SUM(orders.quantity). However, orders isn't included in the FROM section of your query, so you must include it before you can Sum() one of its fields.

如果您具有Access可用，请在查询设计器中构建查询.它可以帮助您了解哪些功能是可能的，并应用正确的Access SQL语法.

If you have Access available, build the query in the query designer. It can help you understand what features are possible and apply the correct Access SQL syntax.

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