Extending WP_Query with Custom Queries and Tables | https://www.ibenic.com/extending-wp-query-custom-queries-tables

clauses.php

<?php

add_filter( 'posts_clauses', 'filter_clauses', 10, 2 );

/**
 * Filtering everything.
 *
 * @param array $clauses Array with all parts of the query.
 * @param WP_Query $wp_query Object.
 * @return string
 */
function filter_clauses( $clauses, $wp_query ) {
 $clauses['where'] = " AND post.post_title LIKE '%SOMETEXT%'";
 return $clauses;
}

join_custom.php

<?php

add_filter( 'posts_join', 'ss_join_table', 20, 2 );

/**
 * Join custom tables.
 *
 * @param string $join String containing all joins.
 * @param WP_Query $wp_query object.
 *
 * @return string
 */
function ss_join_table( $join, $wp_query ) {
 global $wpdb;

 if ( isset( $wp_query->query['ss_package'] ) && absint( $wp_query->query['ss_package'] ) ) {

 $join .= " INNER JOIN $wpdb->sssponsorships as ss_sponsorships on ss_sponsorships.sponsor = $wpdb->posts.ID";

 }

 return $join;
}

join_meta.php

<?php

add_filter( 'posts_join', 'ss_join_table', 20, 2 );

/**
 * Join custom tables.
 *
 * @param string $join String containing all joins.
 * @param WP_Query $wp_query object.
 *
 * @return string
 */
function ss_join_table( $join, $wp_query ) {
 global $wpdb;

 // ... Previous code

 if ( isset( $wp_query->query['ss_content'] ) && absint( $wp_query->query['ss_content'] ) ) {

 $join .= " INNER JOIN $wpdb->postmeta as ss_post_meta on ss_post_meta.meta_value = $wpdb->posts.ID";

 }

 return $join;
}

where_custom.php

<?php

add_filter( 'posts_where', 'ss_where_table', 20, 2 );

/**
 * Add the where clauses.
 *
 * @param string $where Where string.
 * @param WP_Query $wp_query object.
 *
 * @return string
 */
function ss_where_table( $where, $wp_query ) {
 global $wpdb;

 if ( isset( $wp_query->query['ss_package'] ) && absint( $wp_query->query['ss_package'] ) ) {

 $where .= $wpdb->prepare( " AND ss_sponsorships.package=%d", absint( $wp_query->query['ss_package'] ) );

 }

 return $where;
}

where_meta.php

<?php

add_filter( 'posts_where', 'ss_where_table', 20, 2 );

/**
 * Add the where clauses.
 *
 * @param string $where Where string.
 * @param WP_Query $wp_query object.
 *
 * @return string
 */
function ss_where_table( $where, $wp_query ) {
 global $wpdb;
 
 // ... Previous code

 if ( isset( $wp_query->query['ss_content'] ) && absint( $wp_query->query['ss_content'] ) ) {

 $where .= $wpdb->prepare( " AND ss_post_meta.post_id=%d AND ss_post_meta.meta_key='_ss_sponsor'", absint( $wp_query->query['ss_content'] ) );

 }

 return $where;
}

z_plugin_filter_param.php

<?php

/**
 * Hook filters.
 * 
 * @return void
 */
function plugin_filter_custom_param() {
    add_filter( 'posts_where', 'plugin_cpt_filter_where', 20, 2 );
    add_filter( 'posts_join', 'plugin_cpt_filter_join', 20, 2 );
    add_filter( 'posts_distinct', 'plugin_cpt_filter_distinct', 20, 2 );
}

z_plugin_get_cpt.php

<?php

/**
 * Get a custom CPT with get_posts.
 * 
 * @param array $args Array of arguments.
 * @return array Array of posts.
 */
function plugin_get_cpt( $args = array() ) {
 $args = wp_parse_args( $args, array(
 'post_type'         => 'your_cpt',
 'posts_per_page'    => '-1',
 'your_custom_param' => '',
 ));

 if ( isset( $args['your_custom_param'] ) && $args['your_custom_param'] ) {
  $args['suppress_filters'] = false;
  plugin_filter_custom_param();
 }

 $posts = get_posts( $args );

 if ( isset( $args['your_custom_param'] ) && $args['your_custom_param'] ) {
 plugin_unfilter_custom_param();
 }
 
 return $posts;
}

z_plugin_unfilter_param.php

<?php

/**
 * Unhook filters.
 * 
 * @return void
 */
function plugin_unfilter_custom_param() {
    remove_filter( 'posts_where', 'plugin_cpt_filter_where', 20 );
    remove_filter( 'posts_join', 'plugin_cpt_filter_join', 20 );
    remove_filter( 'posts_distinct', 'plugin_cpt_filter_distinct', 20 );
}