SELECT 
  COUNT(
    DISTINCT(tmall_companies.company_id)
  ) 
FROM 
  tmall_companies 
  LEFT JOIN tmall_company_descriptions as company_descr ON company_descr.company_id = tmall_companies.company_id 
  AND company_descr.lang_code = 'en' 
  LEFT JOIN tmall_company_descriptions ON tmall_company_descriptions.company_id = tmall_companies.company_id 
  AND tmall_company_descriptions.lang_code = 'en' 
  LEFT JOIN tmall_absolute_rating AS absolute_rating ON absolute_rating.object_id = tmall_companies.company_id 
  AND absolute_rating.object_type = 'company' 
  LEFT JOIN tmall_vendor_plan_descriptions ON tmall_companies.plan_id = tmall_vendor_plan_descriptions.plan_id 
  AND tmall_vendor_plan_descriptions.lang_code = 'en' 
  LEFT JOIN tmall_discussion ON tmall_discussion.object_id = tmall_companies.company_id 
  AND tmall_discussion.object_type = 'M' 
  LEFT JOIN tmall_discussion_posts ON tmall_discussion_posts.thread_id = tmall_discussion.thread_id 
  AND tmall_discussion_posts.status = 'A' 
  LEFT JOIN tmall_discussion_rating ON tmall_discussion.thread_id = tmall_discussion_rating.thread_id 
  AND tmall_discussion_rating.post_id = tmall_discussion_posts.post_id 
WHERE 
  1 
  AND tmall_companies.status = 'A'

Query time 0.00904

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.030193974,
    "nested_loop": [
      {
        "table": {
          "table_name": "absolute_rating",
          "access_type": "system",
          "possible_keys": ["PRIMARY"],
          "rows": 0,
          "filtered": 0,
          "const_row_not_found": true
        }
      },
      {
        "table": {
          "table_name": "tmall_companies",
          "access_type": "ALL",
          "loops": 1,
          "rows": 2,
          "cost": 0.01034841,
          "filtered": 100,
          "attached_condition": "tmall_companies.`status` = 'A'"
        }
      },
      {
        "table": {
          "table_name": "tmall_discussion",
          "access_type": "eq_ref",
          "possible_keys": ["object_id"],
          "key": "object_id",
          "key_length": "6",
          "used_key_parts": ["object_id", "object_type"],
          "ref": ["tmall.tmall_companies.company_id", "const"],
          "loops": 2,
          "rows": 1,
          "cost": 0.003662852,
          "filtered": 100,
          "attached_condition": "trigcond(tmall_discussion.object_id = tmall_companies.company_id and tmall_discussion.object_type = 'M')"
        }
      },
      {
        "table": {
          "table_name": "tmall_discussion_posts",
          "access_type": "ref",
          "possible_keys": ["thread_id", "thread_id_2"],
          "key": "thread_id",
          "key_length": "3",
          "used_key_parts": ["thread_id"],
          "ref": ["tmall.tmall_discussion.thread_id"],
          "loops": 2,
          "rows": 6,
          "cost": 0.016182712,
          "filtered": 100,
          "attached_condition": "trigcond(tmall_discussion_posts.`status` = 'A' and trigcond(tmall_discussion.thread_id is not null))"
        }
      }
    ]
  }
}