SQL Update

Example Table

We will use the following table named employees for our examples:


    CREATE TABLE employees (
        employee_id INT PRIMARY KEY,
        name VARCHAR(50),
        department VARCHAR(50),
        salary DECIMAL(10, 2)
    );

    INSERT INTO employees (employee_id, name, department, salary) VALUES
    (1, 'Alice', 'HR', 50000.00),
    (2, 'Bob', 'IT', 60000.00),
    (3, 'Charlie', 'Finance', 55000.00);

Employees Table

employee_id	name	department	salary
1	Alice	HR	50000.00
2	Bob	IT	60000.00
3	Charlie	Finance	55000.00

Using the SQL UPDATE Statement

The SQL UPDATE statement is used to modify the existing records in a table.

Example: Updating a Single Record

To update the salary of the employee with employee_id 1:


    UPDATE employees
    SET salary = 52000.00
    WHERE employee_id = 1;

Result:

Query	UPDATE employees SET salary = 52000.00 WHERE employee_id = 1;
Result	employee_id: 1, name: Alice, department: HR, salary: 52000.00 employee_id: 2, name: Bob, department: IT, salary: 60000.00 employee_id: 3, name: Charlie, department: Finance, salary: 55000.00

Example: Updating Multiple Records

To update the department of all employees in the IT department to 'Tech':


    UPDATE employees
    SET department = 'Tech'
    WHERE department = 'IT';