MS Access 2010中的列数? [英] Number of Columns in MS Access 2010?

问题描述

我每周有52列是/否参加会议..我想查询一下以了解在其中输入是或否的列数.有人可以帮助我解决此问题吗?如果您知道任何有关Access查询的推荐站点或社区，请告诉我.谢谢.

I have 52 Yes/No Columns for attendance Weekly .. I want to make query to know the number of columns that put in it a Yes or No... Can anyone help me to solve this problem? Please let me know if you know of any recommend sites or communities for Access queries. Thanks.

推荐答案

我认为这是一个糟糕的设计.它会破坏第一个范式.

I think this is a poor design. It breaks first normal form.

我可以设想一个用户表，一个会议表以及一个将用户与其参加的会议链接起来的多对多JOIN表.

I can envision a user table, a meeting table, and a many-to-many JOIN table linking users with the meetings that they attended.

查询所有会议会告诉您可以参加的日期.

Querying for all the meetings tells you the dates where it's possible to attend.

通过user_meeting JOIN表加入用户表可告诉您给定用户参加了哪些会议.

JOINing the user table with the user_meeting JOIN table tells you which meetings a given user attended.

现在有两组:所有可能的会议和给定用户参加的日期.如果您进行了设置差异，您将看到用户未参加的潜在日期.

Now you have two sets: all the possible meetings and the dates that a given user attended. If you do a set difference, you'll see the potential dates that the user did not attend.

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