SQL INSERT, UPDATE & DELETE

Modifying table data with safe transaction practices

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CRUD operations (Create, Read, Update, Delete) are the foundation of database state management.

Modifying Records

INSERT INTO table (col1, col2) VALUES (val1, val2); inserts new records.

UPDATE table SET col1 = val1 WHERE id = 1; modifies existing data.

DELETE FROM table WHERE id = 1; removes records.

Safe UPDATE and INSERT statements

Try It Yourself »

-- 1. Add new student
INSERT INTO Students (Name, Track, XP)
VALUES ('Jordan Taylor', 'Full Stack', 100);

-- 2. Update XP for a specific student
UPDATE Students
SET XP = XP + 50
WHERE Name = 'Jordan Taylor';

Warning / Pitfall

CRITICAL: Notice the WHERE clause in UPDATE and DELETE statements! If you omit the WHERE clause, ALL records in the table will be updated or deleted!

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Test Yourself With Exercise

+15 XP

What happens if you run "DELETE FROM Customers;" without a WHERE clause?

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