Display all entries matching field of a section

Question

I have two sections:
Games
Publishers

Games has a field called 'GamesPublisher' that is Entries type (set to Publishers)

I have a publisher called 'Microsoft' with an ID of 49.

I want to display all Game entries for the Publisher 'Microsoft' (ie ID 49)

I also want to set the order of the displaying in ASC order based on the field 'GamesCatalogNumber' which is in the section Games.

So far, it looks OK, but I have yet to figure out to limit entries to a specific Publisher. http://www.colorcomputergames.com/tandy-catalog/

{% set entries = craft.entries.section('games').relatedTo(entry) %}
    <ul>
    {% for entry in entries.order('GamesCatalogNumber desc') %}
     <li>{{ entry.GamesCatalogNumber }}: <a href="{{ entry.url }}">{{ entry.title }}</a></li>
    {% endfor %}
    </ul>

    {# Set parameters for prev/next elements list #}
    {% set params = craft.entries.section('publishers').order('title asc') %}

    {# Get the prev/next elements #}
    {% set prevEntry = entry.getPrev(params) %}
    {% set nextEntry = entry.getNext(params) %}

    {# And make sure to only output the links if the element exists #}
    {% if prevEntry %}<a href="{{ prevEntry.url }}">Previous Publisher</a>{% endif %}
    {% if nextEntry %}<a href="{{ nextEntry.url }}">Next Publisher</a>{% endif %}

Answer 1

Looks to me like your solution is mostly correct, except for handling the gamesCatalogNumber. For that you could either:

• test for specific publisher(s) by id or slug
• test if gamesCatalogNumber is empty on the first entry (and assume that the publisher doesn't use catalog numbers), or
• (recommended solution) add a checkbox or lightSwitch field to the publisher called 'usesCatalogNumbers' and test for that.

Something like:

{# publisher template #}

{% if entry.usesCatalogNumbers %}
    {% set games = craft.entries.section('games').relatedTo(entry).order('gamesCatalogNumber desc') %}
{% else %}
    {% set games = craft.entries.section('games').relatedTo(entry).order('title asc') %}
{% endif %}

<ul>
    {% for game in games %}
        <li>{% if entry.usesCatalogNumbers %}{{ entry.gamesCatalogNumber }}: {% endif %}<a href="{{ entry.url }}">{{ entry.title }}</a></li>
    {% endfor %}
</ul>

{% set params = craft.entries.section('publishers').order('title asc') %}
{% set prevEntry = entry.getPrev(params) %}
{% set nextEntry = entry.getNext(params) %}
{% if prevEntry %}<a href="{{ prevEntry.url }}">Previous Publisher</a> {% endif %}{% if nextEntry %}<a href="{{ nextEntry.url }}">Next Publisher</a>{% endif %}

I recommend this (instead of the other options) because it's a bit more explicit and extensible (i.e. allows you to add other publishers that use catalog numbers without modifying the templates).