How to Update a Single Record in SQL Based on a Condition?

Update a Single Record

Write a SQL query to update a single record in a table based on a specific condition.

Solution:

-- Update the salary of an employee with EmployeeID = 1.
UPDATE Employees -- Specify the table to update.
SET Salary = 55000 -- Set the new value for the "Salary" column.
WHERE EmployeeID = 1; -- Apply the update only to the employee with ID 1.

Explanation:

1. Purpose of the Query :

1. The goal is to update the Salary of a specific employee in the Employees table.
2. This demonstrates how to use the UPDATE statement to modify existing data in a table based on a condition.

2. Key Components :

1. UPDATE Employees : Specifies the table where the update will occur.
2. SET Salary = 55000 : Defines the new value for the Salary column.
3. WHERE EmployeeID = 1 : Ensures that the update applies only to the employee with EmployeeID = 1.

3. Why use UPDATE? :

1. The UPDATE statement is used to modify existing records in a table, making it essential for maintaining accurate and up-to-date data.
2. For example, if an employee receives a raise, their salary can be updated in the database using this statement.

4. Real-World Application :

1. For example, in a company database, you might use this query to update the salary of an employee with EmployeeID = 1 to reflect a recent promotion or adjustment.

Additional Notes:

• WHERE clause is critical to ensure that updates are applied only to the intended rows.
• Scenarios where updating a single record is appropriate, such as:
• Adjusting an employee's salary after a promotion or raise.
• Correcting erroneous data in a specific record.
• Important Considerations :
• Always include a WHERE clause to avoid unintentionally updating all rows in the table.
• Verify that the condition in the WHERE clause uniquely identifies the target record.

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