﻿ SQL: List employee id of all the departments 1001 and 2001

# SQL Exercise: List employee id of all the departments 1001 and 2001

## SQL employee Database: Exercise-94 with Solution

[An editor is available at the bottom of the page to write and execute the scripts.]

94. From the following table, write a SQL query to find those employees who work in the department ID 1001 or 2001. Return employee ID, employee name, department ID, department location, and department name.

Sample table: employees

Sample table: department

Sample Solution:

``````SELECT e.emp_id,
e.emp_name,
e.dep_id,
d.dep_location,
d.dep_name
FROM employees e,
department d
WHERE e.dep_id = d.dep_id
AND e.dep_id IN (1001,
2001);
``````

Sample Output:

```emp_id | emp_name | dep_id | dep_location | dep_name
--------+----------+--------+--------------+----------
68319 | KAYLING  |   1001 | SYDNEY       | FINANCE
67832 | CLARE    |   1001 | SYDNEY       | FINANCE
65646 | JONAS    |   2001 | MELBOURNE    | AUDIT
68736 | ADNRES   |   2001 | MELBOURNE    | AUDIT
69324 | MARKER   |   1001 | SYDNEY       | FINANCE
67858 | SCARLET  |   2001 | MELBOURNE    | AUDIT
69062 | FRANK    |   2001 | MELBOURNE    | AUDIT
63679 | SANDRINE |   2001 | MELBOURNE    | AUDIT
(8 rows)
```

Explanation:

The said query in SQL that selects the emp_id, emp_name, dep_id, dep_location, and dep_name from the employees and department tables where the dep_id in the employees table is either 1001 or 2001.

The WHERE clause makes an implicit join between 'employees' and 'department' tables based on the dep_id column and includes only rows where the dep_id in the 'employees' table is either 1001 or 2001.

Relational Algebra Expression:

Relational Algebra Tree:

## Practice Online

Sample Database: employee

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous SQL Exercise: List id, name, department id, location of all employees.
Next SQL Exercise: List employees salary within min_salary and max_salary.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

﻿

## SQL: Tips of the Day

Concatenate strings of a string field in a PostgreSQL 'group by' query:

Input:

```ID   COMPANY_ID   EMPLOYEE
1    1            Anna
2    1            Bill
3    2            Carol
4    2            Dave
```
```SELECT company_id, string_agg(employee, ', ')
FROM mytable
GROUP BY company_id;
```

Output:

```COMPANY_ID   EMPLOYEE
1            Anna, Bill
2            Carol, Dave
```

Database: PostgreSQL

Ref: https://bit.ly/2XTiRjq

We are closing our Disqus commenting system for some maintenanace issues. You may write to us at reach[at]yahoo[dot]com or visit us at Facebook