text: -- e.g1
  SELECT
  PrefecturalID,
  COUNT(*)
  FROM
  Customers
  WHERE
  CustomerClassID = 1
  GROUP BY
  PrefecturalID
  HAVING
  COUNT(*) >= 2
  ;
  
  -- practice1
  SELECT
  PrefecturalID AS 県ID,
  COUNT(*) AS 顧客数
  FROM
  Customers
  WHERE
  PrefecturalID >= 10
  GROUP BY
  PrefecturalID
  HAVING
  COUNT(*) > 1
  ;
  
  -- practice2
  SELECT
  EmployeeID AS 社員ID,
  COUNT(*) AS 支給回数
  FROM
  Salary
  WHERE
  EmployeeID >= 20
  GROUP BY
  EmployeeID
  HAVING
  COUNT(*) >= 12
  ;
  
  -- practice3
  SELECT
  ProductID AS 商品ID,
  COUNT(*)
  FROM
  Sales
  WHERE
  ProductID >= 20 AND ProductID <= 30
  GROUP BY
  ProductID
  HAVING
  COUNT(*) >= 30;
  
  -- practice4
  SELECT
  BloodType AS 血液型,
  COUNT(*) AS　データ数
  FROM
  Employees
  WHERE
  Height >= 165
  GROUP BY
  BloodType
  HAVING
  COUNT(*) >= 5;
  
  -- practice5
  SELECT
  ProductID AS 商品ID,
  SUM(Quantity) AS 数量合計
  FROM
  Sales
  WHERE
  SaleDate >= '2007-06-01'
  GROUP BY
  ProductID
  HAVING
  SUM(Quantity) >= 200;
  