Search a word inside post_content specifically on H1 tag [closed]

As Title implies, Search the value inside the variable of $word inside the tag of column post_title content.

$word = test;
$pQuery = $wpdb->get_results($wpdb->prepare("SELECT * FROM $wpdb->posts
        WHERE post_content LIKE  %s",'<h1>%'.$word.'%</h1>'), ARRAY_A)

ID post_title post_content
1  Hello      <h1>This is a post</h1> <p>This is a description of a post to test if the query is working</p> <h1>Found me test</h1>
2  World      <p>This is a description of a post to test if the query is working</p>

The query should view the data of of this ID

1 - Hello - <h1>This is a post</h1> <p>This is a description of a post to test if the query is working</p> <h1>Found me test</h1>

Answer

This probably won’t work.

1. You need to use $wpdb->esc_like() on the search-term text with % wildcards in it, or prepare will garble your query.

   $wpdb->prepare(
       "SELECT * FROM $wpdb->posts WHERE post_content LIKE  %s",
       $wpdb->esc_like( '<h1>%'.$word.'%</h1>' )
   );
   

2. You need to search for '%<h1>%'.$word.'%</h1>%' because your <h1> tag isn’t at the beginning or the end of your post content. Put % at the beginning and end of your search term.

3. @tadman pointed out that your search won’t work if your <h1> tags contain attributes. There’s nothing you can do about that within the confines of SQL’s LIKE filter.

4. If your post contains more than one <h1> tag your search term will consider words in the entire range between the first and last one.

5. This will be very slow.

There’s an old slogan “If you solve a problem with a regular expression, now you have two problems”. Let’s modify that: “If you solve a problem with SQL’s LIKE, now you have two and a half problems”.

Point 4 could be a problem if your users are not tolerant of glitches.

You may want to consider a search plugin like Relevanssi for this kind of application.