调试 SQL 查询（初学者）

Question

我正在学习 Google Analytics 课程，我们正在练习 JOIN 子句。我收到以下错误：

SELECT 
  name AS employee_name,
  role AS employee_role,
  departments.name AS department_name
FROM 
  `da-first-project-396518.employee_data.employees`
INNER JOIN
  `da-first-project-396518.employee_data.departments` ON
  employees.department_id = employee_data.departments.department_id

我得到的错误是：无法识别的名称：employee_data at [9:3]

我看不出哪里出了问题

Answer 1

您正在为表发送别名

SELECT 
  employees.name AS employee_name,
  employees.role AS employee_role,
  departments.name AS department_name
FROM 
  `da-first-project-396518.employee_data.employees` As employees
INNER JOIN
  `da-first-project-396518.employee_data.departments`  as departments ON
  employees.department_id = departments.department_id

Answer 2

SELECT 
  `da-first-project-396518.employee_data.employees`.name AS employee_name,
  `da-first-project-396518.employee_data.employees`.role AS employee_role,
  `da-first-project-396518.employee_data.departments`.name AS department_name
FROM 
  `da-first-project-396518.employee_data.employees`
INNER JOIN
  `da-first-project-396518.employee_data.departments` 
  ON `da-first-project-396518.employee_data.employees`.department_id = `da-first-project-396518.employee_data.departments`.department_id