SQL SELECT

Overview

SELECT retrieves data from one or more tables. Specify columns (or * for all), filter with WHERE, sort with ORDER BY, and limit results. It is the foundation of read operations in relational databases.

Syntax / Usage

-- Basic select
SELECT id, name, email
FROM users
WHERE active = true
ORDER BY created_at DESC
LIMIT 10;

-- Distinct values
SELECT DISTINCT country FROM customers;

-- Expressions and aliases
SELECT
  name,
  price * quantity AS line_total
FROM order_items;

-- Pagination
SELECT * FROM posts
ORDER BY id
LIMIT 20 OFFSET 40;

Examples

Find recent signups:

SELECT id, email, created_at
FROM users
WHERE created_at >= NOW() - INTERVAL '7 days'
ORDER BY created_at DESC;

Search with pattern matching:

SELECT title, slug
FROM articles
WHERE title ILIKE '%react%'
  AND status = 'published';

Common Mistakes

• SELECT * in production queries—fetch only needed columns
• Missing ORDER BY when order matters—results can be non-deterministic
• Forgetting quotes around string literals (WHERE status = 'active')
• Using LIMIT without ORDER BY for paginated feeds

See Also

where-clause joins group-by crud