11 - UNION , UNION ALL
UNION The UNION command combines the result set of two or more SELECT statements (only distinct values). UNION ALL The Union All extracts all the rows including the duplicates (repeated values) from both the queries. ORIGINAL GENERATED LIST market_1 market_2 Make a final table from market_1 and market_2 which covers all products and duplicate product becomes distinct select product from market_1 UNION select product from market_2; Make a final table from market_1 and market_2 which covers all products and duplicate product stays duplicate se...