SELECT * FROM tbl_news WHERE news_id
 IN (select news_id from
 tbl_tag_relations WHERE tag_id = 20)

SELECT * FROM tbl_news WHERE news_id
 IN (select news_id from
 tbl_tag_relations WHERE tag_id = 20)

SELECT * FROM tbl_news WHERE news_id
 IN (select news_id from
 tbl_tag_relations WHERE tag_id = 20)

SELECT tn.*
FROM tbl_news tn
JOIN tbl_tag_relations ttr ON ttr.news_id = tn.news_id
WHERE ttr.tag_id = 20

SELECT *
FROM tbl_news, tbl_tag_relations
WHERE tbl_tag_relations.tag_id = 20 AND
tbl_news.news_id = tbl_tag_relations.news_id

SELECT news_title, news_body
...
LIMIT 5;

select *
 from tbl_news, tbl_tag_relations
 where
      tbl_tag_relations.tag_id = 20 and
      tbl_news.news_id = tbl_tag_relations.news_id
 limit 20

SELECT news_id, name, blah
FROM tbl_news n
JOIN tbl_tag_relations r ON r.news_id = n.news_id
WHERE r.tag_id IN (20,21,22)