Make Some Changes
Learn how to insert, update, and delete data safely and efficiently in your relational database.
As a data engineer, your job isn’t just to move data around—you’re responsible for keeping it accurate, fresh, and in top shape. Whether you’re prepping a dataset for a data pipeline, scrubbing outdated records from a staging table, or loading a fresh batch into a warehouse, DML commands (INSERT, UPDATE, DELETE) are your go-to SQL tools.
These aren’t just boring commands—they’re like the surgical tools in a data engineer’s kit. Use them right, and your data systems hum along like a well-oiled machine.
Sample table
Before we dive in, meet the table we’ll be working with—think of it as a temporary parking spot for incoming product data before it’s transformed and pushed to production.
product_id | name | price | stock | discontinued |
1 | T-shirt | 19.99 | 50 | false |
2 | Jeans | 49.99 | 20 | false |
3 | Baseball cap | 15.00 | 0 | true |
1. INSERT
Imagine a new product batch just landed, and your pipeline needs to load that data into the products table. Enter the INSERT command.
Syntax
The syntax of INSERT command is:
INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...);
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