Select as subquery

• Subquery at the same line with IN keyword

  SELECT SUM (Sales) FROM Store_Information
  WHERE Store_Name IN (SELECT Store_Name FROM Geography
                       WHERE Region_Name = 'West');

• Subquery in new line after IN keyword

  SELECT SUM (Sales) FROM Store_Information
  WHERE Store_Name IN 
         (SELECT Store_Name FROM Geography
          WHERE Region_Name = 'West');

• Subquery in the same line with EXISTS keyword

  SELECT SUM(Sales) FROM Store_Information
  WHERE EXISTS (SELECT * FROM Geography
                WHERE Region_Name = 'West');

• Subquery in new line after EXISTS keyword

  SELECT SUM(Sales) FROM Store_Information
  WHERE EXISTS 
        (SELECT * FROM Geography
         WHERE Region_Name = 'West');