MySQL Group_Concat重复值 [英] MySQL Group_Concat Repeating Values

问题描述

我正在开发一个名为 PHP-Bouncer 的开源项目，我正在为它编写MySQL查询时遇到问题.基本上，我们有三个表:BouncerRoles，PageInRole和BouncerPageOverrides. BouncerRoles包含访问级别，另外两个表通过外键链接回BouncerRoles，并提供多个附加数据条目.我编写了以下查询，以尝试一次提取我需要的所有角色数据:

I am working on an open source project called PHP-Bouncer, and I'm having issues with a MySQL Query I am writing for it. Basically we have three tables: BouncerRoles, PageInRole, and BouncerPageOverrides. BouncerRoles contains access levels, and the other two tables link back to BouncerRoles via Foreign Key and provide multiple entries of additional data. I have written the following query to attempt to pull all of the role data I need all at once:

select BouncerRoles.RoleID, BouncerRoles.RoleName, 
GROUP_CONCAT(PageInRole.PageName separator '|') as ProvidedPages, 
GROUP_CONCAT(CONCAT(BouncerPageOverrides.OverriddenPage,'&',BouncerPageOverrides.OverridingPage) separator '|') as OverriddenPages 
from BouncerRoles join PageInRole on BouncerRoles.RoleID = PageInRole.RoleID 
join BouncerPageOverrides on BouncerRoles.RoleID = BouncerPageOverrides.RoleID
group by BouncerRoles.RoleID;

此查询的目标是提供RoleID，RoleName，提供页面的以竖线分隔的列表和替代的竖线分隔的列表(以overriddenpage& overridingpage的形式).除查询的最后一列外，其他所有内容都可以正常工作，查询的最后一遍如此重复(以CSV格式输出):

The Goal of this query is to provide the RoleID, RoleName, a pipe delimited list of provided pages, and a pipe delimited list of overrides (in the form of overriddenpage&overridingpage). Everything works except the last column of the query, which repeats the entries it finds over and over like this (output in CSV format):

RoleID,RoleName,ProvidedPages,OverriddenPages
2,Exchange,exchange-how.php|exchange-support.php|exchange.php|premium-promo.php|exchange-resorts.php|premiumplus-promo.php|exchange-deposit.php|exchange-requestdestination.php,whyexchange.php&exhange.php|whyexchange.php&exhange.php|whyexchange.php&exhange.php|whyexchange.php&exhange.php|whyexchange.php&exhange.php|whyexchange.php&exhange.php|whyexchange.php&exhange.php|whyexchange.php&exhange.php
3,Premium,premiumplus-promo.php|premium-cruises.php|premium-resorts.php|premium-condohome.php|premium-hotelaircar.php|premium.php|premium-restaurants.php|premium-overview.php,premium-promo.php&premium.php|premium-promo.php&premium.php|premium-promo.php&premium.php|premium-promo.php&premium.php|premium-promo.php&premium.php|premium-promo.php&premium.php|premium-promo.php&premium.php|premium-promo.php&premium.php
4,"Premium Plus",premiumplus-exclusiveescapes.php|premiumplus.php|premiumplus-overview.php|premiumplus-concierge.php|premiumplus-airportlounge.php,premiumplus-promo.php&premiumplus.php|premiumplus-promo.php&premiumplus.php|premiumplus-promo.php&premiumplus.php|premiumplus-promo.php&premiumplus.php|premiumplus-promo.php&premiumplus.php

我在查询中是否做错了什么导致这种情况?

Is there something I've done wrong in my query to cause this?

推荐答案

您可能正在将一个表与具有1..n关系的两个表连接在一起，从而产生重复的结果.

You are probably joining a table with two tables on 1..n relationships, producing duplicate results.

• 使用GROUP_CONCAT( DISTINCT ...)或

使用两个子查询:在每个子查询中，对两个表中的每个表均使用GROUP_CONCAT()和group by.然后将两个子查询和主表连接起来.

Use two subqueries: in each one use GROUP_CONCAT() with group by on each of the 2 tables. Then join the two subqueries and the main table.

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