衍生

計算一個或多個新欄位。

derive {
  name = expression,
  # or
  column,
}

範例

from employees
derive gross_salary = salary + payroll_tax

SELECT
  *,
  salary + payroll_tax AS gross_salary
FROM
  employees

from employees
derive {
  gross_salary = salary + payroll_tax,
  gross_cost = gross_salary + benefits_cost
}

SELECT
  *,
  salary + payroll_tax AS gross_salary,
  salary + payroll_tax + benefits_cost AS gross_cost
FROM
  employees