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内连接

简单 11-join 连接 joininner

列出每位员工及其所在部门的名称。

  • 通过 dept_id 把员工和部门对上。
  • 只输出能对上部门的员工:dept_id 为 null 的员工、dept_id 在部门表里找不到的员工都不输出;没有员工的部门也不输出。
  • null 键不与任何行匹配。

输入

  • employees(emp_id, name, dept_id, manager_id, hire_date, salary, title, email)
  • departments(dept_id, dept_name, parent_dept_id)

输出

列为 name, dept_name,行顺序不限。

输入表 (case base,共 2 个 case:base、orphans)

employees hr/employees
#emp_idint64namestringdept_idint64manager_idint64hire_datedatesalaryint64titlestringemailstring
1 1 Grace Liu 1 null 2015-10-01 98000 CEO grace.liu@corp.example
2 2 Leo Wang 2 1 2017-09-09 72000 VP Engineering leo.wang@corp.example
3 3 Sara Chen 3 1 2020-06-05 70000 VP Sales sara.chen@corp.example
4 4 Lucas Zhang 4 2 2023-04-20 52000 Engineering Manager lucas.zhang@corp.example
5 5 Mia Zhao 5 2 2016-07-16 52000 Data Manager mia.zhao@corp.example
6 6 Kevin Wu 3 3 2016-10-23 45000 Sales Manager kevin.wu@corp.example
7 7 Lily Xu 6 4 2025-03-17 48000 Infra Lead lily.xu@corp.example
8 8 Tom Huang 4 4 2022-01-03 46000 Senior Engineer tom.huang@corp.example
9 9 Liam Zhou 4 4 2020-10-01 39000 Software Engineer liam.zhou@corp.example
10 10 Nina Yang 4 4 2020-10-02 39000 Software Engineer nina.yang@corp.example
11 11 Oscar Lin 4 8 2022-07-15 26000 Junior Engineer oscar.lin@corp.example
12 12 Linda Ma 5 5 2016-08-25 41000 Data Engineer linda.ma@corp.example
13 13 Eric Sun 5 5 2021-09-09 33000 Data Analyst eric.sun@corp.example
14 14 Ivy He 5 5 2018-05-29 41000 Data Engineer ivy.he@corp.example
15 15 Lei Gao 5 12 2016-06-02 27000 Junior Data Engineer lei.gao@corp.example
16 16 Hao Guo 6 7 2016-12-18 44000 Site Reliability Engineer hao.guo@corp.example
17 17 Fang Luo 6 7 2020-11-11 38000 Infra engineer fang.luo@corp.example
18 18 Jun Liang 6 16 2020-09-08 25000 Junior Engineer jun.liang@corp.example
19 19 Dana Song 3 6 2016-10-13 31000 Account Executive dana.song@corp.example
20 20 Victor Tang 3 6 2018-09-12 31000 Account Executive victor.tang@corp.example
显示前 20 行,共 40 行
departments hr/departments
#dept_idint64dept_namestringparent_dept_idint64
1 1 Headquarters null
2 2 Engineering 1
3 3 Sales 1
4 4 Platform 2
5 5 Data 2
6 6 Infra 4
7 7 Legal 1
8 8 Research 5
共 8 行

期望输出 (case base,行顺序不限)

#nameStringdept_nameString
1 Grace Liu Headquarters
2 Leo Wang Engineering
3 Sara Chen Sales
4 Lucas Zhang Platform
5 Mia Zhao Data
6 Kevin Wu Sales
7 Lily Xu Infra
8 Tom Huang Platform
9 Liam Zhou Platform
10 Nina Yang Platform
11 Oscar Lin Platform
12 Linda Ma Data
13 Eric Sun Data
14 Ivy He Data
15 Lei Gao Data
16 Hao Guo Infra
17 Fang Luo Infra
18 Jun Liang Infra
19 Dana Song Sales
20 Victor Tang Sales
21 Wen Han Sales
22 Lu Feng Sales
23 Yan Deng Sales
24 Zoe Cao Legal
25 Ping Peng Platform
26 Qing Xie Platform
27 Xin Cai Data
28 Bob Pan Platform
29 Chen Du Infra
30 Amy Yu Sales
31 Larry Ren Engineering
32 Wei Shi Data
33 Zhang Min Platform
34 王磊 Sales
35 李静 Data
36 Henry Kong Infra
37 Logan Bai Platform
38 Sophie Fan Sales
共 38 行