SQL Query:
(SELECT id, product_name, description, price, img1, img2, img3, img4, 'product' AS source
FROM product
WHERE status='1' AND cat_id='4'
AND (product_name LIKE '%%' OR description LIKE '%%') AND scat_id='9')
UNION
(SELECT id, product_name, description, price, img1, img2, img3, img4, 'productexpo' AS source
FROM productexpo
WHERE status='1' AND cat_id='4'
AND (product_name LIKE '%%' OR description LIKE '%%') AND scat_id='9')