WordpressでカテゴリーAのBかつC該当しており、さらにカテゴリーDのEまたはFまたはG...に該当する投稿を取得する ref: https://qiita.com/Go-Noji/items/7604cc3b0cf68147af5e

file0.php

  //nonceの検証（失敗したらスクリプトが停止）
  check_ajax_referer('ajaxNonce', 'nonce');

  //グローバルからwpdbクラスを呼び出し
  global $wpdb;

  //検索条件である地域カテゴリー
  $categories = isset($_POST['categories']) ? (array)$_POST['categories'] : array();

  //追加WHERE文の作成
  $wheres[] = array;
  foreach ((array)$categories as $category)
  {
    //そもそもint型にできない or 整数値ではなさげな値を弾く
    if ( ! is_scalar($category) || ! ctype_digit((string)$category))
    {
      continue;
    }

    $wheres[] = " wp_term_taxonomy.term_taxonomy_id = ".(int)esc_sql($category)." ";
  }
  $where = $wheres ? '('.implode('OR', ).$wheres.')' : '';

  //LIMIT, OFFSET
  $limit = isset($_POST['limit']) && is_scalar($_POST['limit']) ? (int)$_POST['limit'] : 30;
  $offset = isset($_POST['offset']) && is_scalar($_POST['offset']) ? (int)$_POST['offset'] : 0;

  //「女性向け(スラッグ名=forWormen)」「スイーツ推し(スラッグ名=sweets)」のカテゴリーを持つ投稿のみ取得
  //ここで取得する列の最大値は実際に返す列より一つ多く取得する
  //なぜなら、次の記事が存在するか判定するため
  if ($whereCount)
  {
    $query = $wpdb->prepare("
    SELECT DISTINCT wp_posts.* 
    FROM `wp_term_taxonomy` 
    LEFT JOIN `wp_term_relationships` ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id
    LEFT JOIN `wp_posts` ON wp_term_relationships.object_id = wp_posts.ID 
    WHERE {$where} 
    AND wp_term_taxonomy.taxonomy = 'area' 
    AND ID IN(SELECT DISTINCT wp_posts.ID
      FROM `wp_terms`
      LEFT JOIN `wp_term_taxonomy` ON wp_terms.term_id = wp_term_taxonomy.term_id
      LEFT JOIN `wp_term_relationships` ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id
      LEFT JOIN `wp_posts` ON wp_term_relationships.object_id = wp_posts.ID
      WHERE (wp_terms.slug = 'forWomen' OR wp_terms.slug = 'sweets')
      AND wp_posts.post_type = 'post' 
      AND wp_posts.post_status = 'publish' 
      AND wp_term_taxonomy.taxonomy = 'category' 
      GROUP BY wp_posts.ID 
      HAVING COUNT(wp_posts.ID) = 2)
    LIMIT %d, %d
    ", $offset, $limit + 1);
  }
  else
  {
    $query = $wpdb->prepare("
    SELECT wp_posts.* 
    FROM `wp_terms`
    LEFT JOIN `wp_term_taxonomy` ON wp_terms.term_id = wp_term_taxonomy.term_id
    LEFT JOIN `wp_term_relationships` ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id
    LEFT JOIN `wp_posts` ON wp_term_relationships.object_id = wp_posts.ID
    WHERE (wp_terms.slug = 'forWomen' OR wp_terms.slug = 'sweets')
    AND wp_posts.post_type = 'post' 
    AND wp_posts.post_status = 'publish' 
    AND wp_term_taxonomy.taxonomy = 'category' 
    GROUP BY wp_posts.ID
    HAVING COUNT(wp_posts.ID) = 2 
    LIMIT %d, %d
    ", $offset, $limit + 1);
  }

  //データ取得
  $data = $wpdb->get_results($query, ARRAY_A);

  //次の記事が存在するかを情報に加える
  $isNext = isset($data[$limit]) && $data[$limit] ? TRUE : FALSE;

  //上記存在判定のために余分に取っておいた列を詰める
  if (isset($data[$limit]) && $data[$limit])
  {
    array_pop($data);
  }

  //jsonに加工してデータを吐き出す
  print json_encode(compact('data', 'isNext'), TRUE);

file1.sql

    SELECT wp_posts.* 
    FROM `wp_terms`
    LEFT JOIN `wp_term_taxonomy` ON wp_terms.term_id = wp_term_taxonomy.term_id
    LEFT JOIN `wp_term_relationships` ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id
    LEFT JOIN `wp_posts` ON wp_term_relationships.object_id = wp_posts.ID
    WHERE (wp_terms.slug = 'forWomen' OR wp_terms.slug = 'sweets')
    AND wp_posts.post_type = 'post' 
    AND wp_posts.post_status = 'publish' 
    AND wp_term_taxonomy.taxonomy = 'category' 
    GROUP BY wp_posts.ID
    HAVING COUNT(wp_posts.ID) = 2 
    LIMIT 0, 30

file2.sql

    SELECT DISTINCT wp_posts.* 
    FROM `wp_term_taxonomy` 
    LEFT JOIN `wp_term_relationships` ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id
    LEFT JOIN `wp_posts` ON wp_term_relationships.object_id = wp_posts.ID 
    WHERE (wp_term_taxonomy.term_taxonomy_id = 1 OR wp_term_taxonomy.term_taxonomy_id = 2 OR wp_term_taxonomy.term_taxonomy_id = 3) 
    AND wp_term_taxonomy.taxonomy = 'area' 
    AND ID IN(SELECT DISTINCT wp_posts.ID
      FROM `wp_terms`
      LEFT JOIN `wp_term_taxonomy` ON wp_terms.term_id = wp_term_taxonomy.term_id
      LEFT JOIN `wp_term_relationships` ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id
      LEFT JOIN `wp_posts` ON wp_term_relationships.object_id = wp_posts.ID
      WHERE (wp_terms.slug = 'forWomen' OR wp_terms.slug = 'sweets')
      AND wp_posts.post_type = 'post' 
      AND wp_posts.post_status = 'publish' 
      AND wp_term_taxonomy.taxonomy = 'category' 
      AND 
      GROUP BY wp_posts.ID 
      HAVING COUNT(wp_posts.ID) = 2)
    LIMIT 0, 30