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Tutorials > SQL > Inserting, updating, and deleting data

Inserting, updating, and deleting data

In SQL, you can insert, update, and delete data stored in relational databases. Here are examples of how to perform each of these operations in SQL:

  • Inserting data: The INSERT INTO statement is used to insert data into a table.
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INSERT INTO customers (first_name, last_name, email)
VALUES ('John', 'Doe', 'johndoe@example.com');

In this example, the INSERT INTO statement is used to insert a new row into the customers table. The columns first_name, last_name, and email are specified, and the values 'John', 'Doe', and 'johndoe@example.com' are assigned to these columns.

  • Updating data: The UPDATE statement is used to modify existing data in a table.
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UPDATE customers
SET email = 'johndoe123@example.com'
WHERE first_name = 'John' AND last_name = 'Doe';

In this example, the UPDATE statement is used to modify the email address of a customer with the first name 'John' and last name 'Doe' in the customers table. The SET clause is used to specify the new email address, and the WHERE clause is used to identify the specific row to be updated.

  • Deleting data: The DELETE FROM statement is used to remove data from a table.
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DELETE FROM customers
WHERE first_name = 'John' AND last_name = 'Doe';

In this example, the DELETE FROM statement is used to remove the row for the customer with the first name 'John' and last name 'Doe' from the customers table. The WHERE clause is used to identify the specific row to be deleted.

It is important to use these operations carefully, as they can result in permanent data loss. It is always a good practice to back up your data before performing any update or delete operations.



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