SQL SELECT Statement

SELECT retrieves data from one or more tables. It's the statement you'll write more than any other in SQL.

Syntax

SELECT column1, column2
FROM table_name;

-- every column
SELECT * FROM table_name;

Sample Table: employees

Example

SELECT name, department
FROM employees;

Output:

Why Not Always Use SELECT *?

SELECT * is convenient while exploring data, but in real applications it's usually avoided: it pulls columns you don't need (wasting bandwidth and memory), and it silently breaks if the table's columns change later. Naming columns explicitly is the professional default.

Computed Columns

SELECT name, salary, salary * 12 AS annual_salary
FROM employees;

You can select expressions, not just raw columns — covered further in Aliases.

Common Mistakes

• Using SELECT * in production application code instead of named columns
• Forgetting that SELECT alone doesn't filter or sort — that's WHERE and ORDER BY

Interview Relevance

The very first thing most SQL interviews check is whether you can write a clean, correctly-scoped SELECT — get comfortable with it before anything else.

Practice Question

Write a query that selects each employee's name and their salary expressed as a monthly figure, assuming salary stores an annual value.

Related SQL Notes

• SELECT DISTINCT
• WHERE Clause
• Aliases