Your First SELECT

The SELECT Statement

The SELECT statement is the most fundamental SQL command. It retrieves data from one or more tables. Every query you write will start with SELECT.

Selecting All Columns

The asterisk (*) is a wildcard that means "all columns":

SELECT * FROM products;

This returns every column and every row from the products table. It is useful for quick exploration, but in production code you should almost always list the specific columns you need.

Tip: Avoid SELECT * in application code. It fetches more data than necessary, makes your queries fragile when columns are added or reordered, and can hurt performance on large tables.

Captain Picard would probably say: "Computer, show me everything about this planet." That is his version of SELECT * --- convenient on the bridge, but in production code, you want to be more specific.

Selecting Specific Columns

List the columns you want, separated by commas:

SELECT name, price FROM products;

This returns only the name and price columns. The order of columns in the result matches the order you list them, not the order they were defined in the table.

SELECT price, name FROM products;

This returns price first, then name.

Column Aliases with AS

You can rename columns in the output using AS. This does not change the underlying table, only the column name in the result set:

SELECT name AS product_name, price AS cost FROM products;

Aliases are useful when column names are ambiguous, when joining multiple tables, or when you want more readable output.

If your alias contains spaces or special characters, wrap it in double quotes:

SELECT name AS "Product Name", price AS "Unit Price" FROM products;

Expressions in SELECT

You can use expressions and calculations in your SELECT list:

SELECT name, price, price * 1.1 AS price_with_tax FROM products;

This adds a computed column that shows the price with a 10% tax applied. The original price column is unchanged.

Removing Duplicates with DISTINCT

If a column contains repeated values, use DISTINCT to return only unique values:

SELECT DISTINCT category FROM products;

This returns each category exactly once, no matter how many products belong to it.

Your Task

Select only the name and price columns from the products table.