Ravindra BagaleCourses & study guides

10. MySQL Part 1: Install, Create, Insert and SELECT

10.4 Inserting Data

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INSERT INTO students (name, email, city, age, fees_paid, joined_on) VALUES
 ('Ravindra Bagale', 'ravindra@example.com', 'Pune',         NULL, 15000, '2026-01-05'),
 ('Shraddha Bagale', 'shraddha@example.com', 'Pune',           29, 15000, '2026-01-05'),
 ('Ruhi Bagale',     'ruhi@example.com',     'Nashik',         21, 12000, '2026-02-10'),
 ('Shahrukh',        'shahrukh@example.com', 'Nagpur',         24,  8000, '2026-02-15'),
 ('Amir',            'amir@example.com',     'Kolhapur',       26, 15000, '2026-03-01'),
 ('Salman',          'salman@example.com',   'Solapur',        23,     0, '2026-03-03'),
 ('Zoya',            'zoya@example.com',     'Sambhaji Nagar', 22, 10000, '2026-03-20'),
 ('Ravina',          'ravina@example.com',   'Nagpur',         25, 12000, '2026-04-02'),
 ('Raja',            NULL,                   'Nashik',         20,  5000, '2026-04-11'),
 ('Rani',            'rani@example.com',     'Pune',           27, 15000, '2026-04-18');

INSERT INTO courses (course_name, duration_wk) VALUES
 ('Networking', 4), ('Linux', 6), ('AWS', 8), ('Ethical Hacking', 10), ('SOC Analyst', 6), ('Cloud Security', 6);

INSERT INTO enrollments (student_id, course_id, score) VALUES
 (1,1,92),(1,4,88),(2,2,79),(3,1,65),(3,2,71),(4,4,58),(5,3,84),
 (6,1,45),(7,5,90),(8,4,76),(8,5,81),(10,3,67);

SELECT COUNT(*) FROM students;     -- 10

Student 9 (Raja) is deliberately in no course, course 2 (Linux) has two students and course 6 (Cloud Security) has none – we will need these for JOINs. Ravindra's age is left NULL on purpose for the NULL examples.

Why this matters for security

Every INSERT built from user input must use prepared statements (section 9.7). A value like '), ('hacker','x inside a string-concatenated INSERT can add extra rows or break the query – that is SQL injection in an INSERT.

Ravindra Bagale's Tip

Many students write INSERT INTO students VALUES (...) without a column list – then when a column is added later, the query breaks. Always write the column names. And put text in single quotes, like 'Pune', and numbers without quotes.

Practice task

Insert the sample data exactly as shown, then add yourself as a new student and one new course of your choice.