複数のテーブルから抽出 (select [col] from [tab1]) union (select [col] from [tab2]); # 3つ以上の union も可能 (select [col] from [tab1]) union (select [col] from [tab2]) union (select [col] from [tab3]); # 条件付き抽出 (select [col] from [t…