# Queries ## Insert queries 1. Insert a row with all columns ```sql INSERT INTO students VALUES (1, 'Tantia', 'Tope', 't@t.com', '1234567890', 1); ``` 2. Insert a row with some columns ```sql INSERT INTO students (first_name, last_name) VALUES ('Tantia', 'Tope'); ``` --- ## Select Queries 1. Get all students ```sql SELECT * FROM students; ``` 2. Get first and last name of all students ```sql SELECT first_name, last_name FROM students; ``` 3. Get first name of all students with output column name as `Student Name` ```sql SELECT first_name AS "Student Name" FROM students; ``` 4. Get all unique addresses of all students ```sql SELECT DISTINCT address FROM students; ``` 5. Get all students with ID equal to 1 ```sql SELECT * FROM students WHERE id = 1; ``` 6. Get all students with IQ greater than 150 ```sql SELECT * FROM students WHERE iq > 150; ``` 7. Get all students with IQ less than 100 ```sql SELECT * FROM students WHERE iq < 100; ``` 8. Get all students with IQ greater than 100 and less than150 ```sql SELECT * FROM students WHERE iq > 100 AND iq < 150; ``` 9. Get all students with IQ greater than 100 or less than 150 ```sql SELECT * FROM students WHERE iq BETWEEN 100 AND 150; ``` 10. Get all students with first name `Tantia` ```sql SELECT * FROM students WHERE first_name = 'Tantia'; ``` 11. Get all students with first name `Tantia` and last name `Tope` ```sql SELECT * FROM students WHERE first_name = 'Tantia' AND last_name = 'Tope'; ``` 12. Get all students with first name `John` or first name `Mycroft` ```sql SELECT * FROM students WHERE first_name = 'John' OR first_name = 'Mycroft'; ``` 13. Get all students with name `John Watson` or `Mycroft Holmes` ```sql SELECT * FROM students WHERE (first_name = 'John' AND last_name = 'Watson') OR (first_name = 'Mycroft' AND last_name = 'Holmes'); ``` 14. Get all students without the first name `John` ```sql SELECT * FROM students WHERE first_name <> 'John'; ``` 15. Get all students without the first name `John` or last name `Mycroft` ```sql SELECT * FROM students WHERE first_name <> 'John' AND last_name <> 'Mycroft'; ``` 16. Get all students with first name starting with `T` ```sql SELECT * FROM students WHERE first_name LIKE 'T%'; ``` 17. Get all students with last name ending with `walker` ```sql SELECT * FROM students WHERE last_name LIKE '%walker'; ``` 18. Get all students with first name containing `T` ```sql SELECT * FROM students WHERE first_name LIKE '%T%'; ``` 19. Get all students with last name in the format `___walker` ```sql SELECT * FROM students WHERE last_name LIKE '___walker'; ``` 20. Get all students in Jhansi and London ```sql SELECT * FROM students WHERE address IN ('Jhansi', 'London'); ``` 21. Get all students which do not have a batch id ```sql SELECT * FROM students WHERE batch_id IS NULL; ``` 22. Get the first 5 students ```sql SELECT * FROM students LIMIT 5; ``` 23. Get the first 5 students sorted by IQ ```sql SELECT * FROM students ORDER BY iq LIMIT 5; ``` 24. Get the first 5 students sorted by IQ in descending order ```sql SELECT * FROM students ORDER BY iq DESC LIMIT 5; ``` 25. Get the first 5 students sorted by IQ in descending order and then by first name ```sql SELECT * FROM students ORDER BY iq DESC, first_name LIMIT 5; ``` --- ## Update Queries 1. Update a row ```sql UPDATE students SET first_name = 'Tantia' WHERE id = 1; ``` 2. Update a row with a condition ```sql UPDATE students SET first_name = 'Tantia' WHERE id = 1 AND first_name = 'John'; ``` 3. Update multiple columns ```sql UPDATE students SET first_name = 'Tantia', last_name = 'Tope' WHERE id = 1 AND first_name = 'John'; ``` ## Delete Queries 1. Delete a row with a condition ```sql DELETE FROM students WHERE id = 1 AND first_name = 'John'; ``` 2. Delete a multiple rows ```sql DELETE FROM students WHERE id IN (1, 2, 3); ``` ## Joining Queries 1. Get first name and last name of all students and their batch names ```sql SELECT students.first_name, students.last_name, batches.name FROM students JOIN batches ON students.batch_id = batches.id; ``` 2. Get first name and last name of all students and their instructor names ```sql SELECT s.first_name, s.last_name, i.first_name, b.name, i.last_name FROM students s JOIN batches b ON s.batch_id = b.id JOIN instructors i ON b.instructor_id = i.id; ```