Question

我尝试过子查询和连接查询，但我无法得到正确的答案，因为我需要从不同的表中检索数据。这就是我想要做的事情：

显示部门名称，街道地址和城市的部门位置和国家名称部门所在地的员工名为Den Raphaely的名字

我有这样的桌子。

COUNTRIES TABLE

COUNTRY_ID
COUNTRY_NAME
的region_id

DEPARTMENT TABLE

部门标识
DEPARTMENT_NAME
MANAGER_ID
LOCATION_ID

员工表

如first_name
姓氏
电子邮件
电话
薪水
佣金
部门标识
JOB_ID
HIRE_DATE

JOBS_HISTORY TABLE

EMPLOYEE_ID
起始日期
END_DATE
JOB_ID
部门标识

JOB TABLE

JOB_ID
Min_salary
MAX_SALARY

LOCATIONS TABLE

LOCATION_ID
STREET_ADDRESS
POSTAL_CODE
国家
COUNTRY_ID

REGION TABLE

的region_id
REGION_NAME

这是尝试过的查询

SELECT Employees.FIRST_NAME, Employees.LAST_NAME,
Departments.DEPARTMENT_NAME, Locations.Street_Address,
Locations.City, Countries.Country_Name FROM
Countries INNER JOIN Locations ON
Countries.Country_ID=Locations.Country_ID
INNER JOIN Departments ON
Locations.Location_id=Departments.LOCATION_ID
INNER JOIN Employees ON
Departments.DEPARTMENT_ID = (SELECT Employees.DEPARTMENT_ID FROM Employees
WHERE FIRST_NAME LIKE 'Den' AND LAST_NAME LIKE 'Raphaely')

Answer 1

您的JOIN与过滤（WHERE）逻辑混淆：

SELECT 
  Employees.FIRST_NAME, 
  Employees.LAST_NAME, 
  Departments.DEPARTMENT_NAME, 
  Locations.Street_Address, 
  Locations.City, 
  Countries.Country_Name 
FROM Countries 
   INNER JOIN Locations ON Countries.Country_ID=Locations.Country_ID
   INNER JOIN Departments ON Locations.Location_id=Departments.LOCATION_ID
   INNER JOIN Employees ON Departments.DEPARTMENT_ID = Employees.DEPARTMENT_ID
WHERE Employees.FIRST_NAME LIKE 'Den' AND Employees.LAST_NAME LIKE 'Raphaely'

Answer 2

SELECT e.first_name, e.last_name, d.department_name, l.street_address, l.city, c.country_name
FROM
employees e
INNER JOIN
department d
ON e.department_id = d.department_id
INNER JOIN
location l
ON d.location_id = l.location_id
INNER JOIN country c
ON c.country_id = l.country_id
WHERE
e.first_name = 'Den'
AND
e.last_name = 'Raphaely'

来自多个表的SQL查询 - 连接不起作用

2 个答案: