Understanding wordpress the_content - mysql

Question

I have been asked to tweak a friend's website. The website was built for them using Wordpress by an agency they no longer work with. Problem is, I don't know very much about Wordpress, so I have some basic questions…
I can see (by comparing the source as viewed in my browser to the php templates that I can edit through the Wordpress interface) that the elements I need to modify are generated by the page's call to "the_content()". I don't really understand what this function does, but I think it pulls content for a given page from the MySQL database. Is that right?
I suspect that the Wordpress interface alone won't be enough to let me modify elements that come out of that database. Is that correct? How does anyone change, for example, the specific arrangement of text and images on a page if the relevant markup is fetched by "get_content()"?

Answer 1

When developing for WordPress or even just tweaking, it's really important to get at least a general understanding of the "loop" and how we use it for output. In order to output the content you need to call the method within the loop. If it's not within the loop it won't get inserted into your page.
(It works this way with all of your pages... index.php, page.php, single.php, post.php, etc... Your methods need to be placed within the loop in order for them to display within that page.)
Here's a simple example of the way the loop is used to output the title and content of posts:
<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?> // loop start
<h1><?php the_title() ;?></h1>
<?php the_content(); ?>
<?php endwhile; else: ?> // loop end
<p>Sorry, this page does not exist</p>
<?php endif; ?>
If you take a look at any standard WordPress theme (take Twenty Fourteen, for example), you'll find that the_content() is output together with calls to other elements (in this case - the_title()). If you want to want to change the arrangement of the specific elements within your page, just modify the order as they are within your loop, or check the WordPress Codex for additional options/methods.
Here's a short list of some other things you can display:
next_post_link – Displays a link to the post published chronologically after the current post.
previous_post_link – Displays a link to the post published chronologically before the
current post.
the_category – Displays the category or categories associated to the post or page being viewed.
the_author – Displays the author of the post or page.
the_content – Displays the main content for a post or page.
the_excerpt – Displays the first 55 words of a post’s main content then with a [...] or read more link that goes to the full post. The length of excerpts can be controlled by using this slightly advanced method or by using the Excerpt field on the post edit page.
the_ID – Displays the ID for the post or page.
the_meta – Used to display custom fields.
the_shortlink – Displays a link to the page or post using the url of the site using
the ID of the post or page.
the_tags – Displays the tag or tags associated with the post.
the_title – Displays the title of the post or page.
the_time – Displays the time or date for the post or page. This can be customized using the standard php date function formatting.
If you want to further customize some of these methods, you can do that within functions.php. Otherwise, all styling is done within your styles.css.

Answer 2

Probably your content is being generated by a shortcode.
You can modify the content that wordpress fetches from the database with the_content filter:
// returns the content of $GLOBALS['post']
// if the page is called 'debug'
function my_the_content_filter($content) {
// assuming you have created a page/post entitled 'debug'
if ($GLOBALS['post']->post_name == 'debug') {
return var_export($GLOBALS['post'], TRUE );
}
// otherwise returns the database content
return $content;
}
add_filter( 'the_content', 'my_the_content_filter' );
maybe its not the best solution but you can modify the content before it gets output.
source