Если я вас понял, вам нужен полнотекстовый поиск .
Вот код, который может вам помочь.
SELECT id, title, content, link FROM (
SELECT news_id AS id, news_title AS title, news_description AS content,
MATCH (news_description, news_title) AGAINST ('$keyword') AS relevance FROM tbl_news
UNION ALL
SELECT package_id AS id, package_title AS title, package_description AS content,
MATCH (package_description, package_title) AGAINST ('$keyword') AS relevance FROM tbl_packages
)temp_sort_table
WHERE relevance >0 ORDER BY relevance DESC LIMIT $offset,$limit