PostgreSQL Exercises
Fill in the blanks to test your knowledge.
1
Create a new table called employees
TABLE employees (
id SERIAL PRIMARY KEY,
name VARCHAR(100)
);
2
Insert a row into the employees table
INTO employees (name) VALUES ('Alice');
3
Select employees joined with departments
SELECT e.name, d.dept_name
FROM employees e
JOIN departments d ON e.dept_id = d.id;
4
Update an employee's name
employees SET name = 'Bob' WHERE id = 1;
5
Create an index on the name column
CREATE idx_name ON employees(name);
6
Delete rows matching a condition
FROM employees WHERE id = 5;
7
Use DISTINCT to remove duplicate values
SELECT department FROM employees;
8
Filter groups using HAVING
SELECT dept_id, COUNT(*) FROM employees
GROUP BY dept_id
COUNT(*) > 5;