July 22nd, 2023
Welcome back to our SQL blog series! In the last post, we covered how to update data in a table using the UPDATE command. In this post, we will cover how to delete data from a table using the DELETE command.
Deleting Data from a Table
To delete data from a table using SQL, you can use the DELETE command. Here's an example:
DELETE FROM mytable WHERE name = 'John Doe';
This command deletes the row in the "mytable" table where the "name" column is "John Doe". You can also delete multiple rows at once by using the WHERE clause to specify a condition that matches multiple rows. Here's an example:
DELETE FROM mytable WHERE age > 25;
This command deletes all rows in the "mytable" table where the "age" column is greater than 25.
Deleting All Rows
If you want to delete all rows from a table, you can use the DELETE command without a WHERE clause. Here's an example:
DELETE FROM mytable;
This command deletes all rows from the "mytable" table.
Dropping a Table
If you want to delete a table entirely, you can use the DROP TABLE command. Here's an example:
DROP TABLE mytable;
This command deletes the entire "mytable" table.
Be careful when using the DELETE and DROP TABLE commands, as they permanently remove data from your database.
Conclusion
In this post, we covered how to delete data from a table using the DELETE command. We also covered how to delete multiple rows, delete all rows, and drop a table entirely. In the next post, we will cover how to use prepared statements in SQL to help prevent SQL injection attacks. Stay tuned!