Reading Data (SELECT)

The most basic SQL statement is SELECT. It reads data.

Read everything

SELECT * FROM users;

This returns all rows and all columns from the users table.

Read only what you need

SELECT name, age FROM users;

This returns only name and age.

Filter with WHERE

SELECT * FROM users
WHERE age >= 20;

This returns only users who are 20 or older.

Multiple Conditions (AND / OR)

SELECT * FROM users
WHERE age >= 20 AND name = 'Alex';

AND returns only rows that satisfy both conditions.

SELECT * FROM users
WHERE age < 15 OR age > 60;

OR returns rows that satisfy at least one of the conditions.

Sort (ORDER BY)

SELECT * FROM users
ORDER BY age DESC;

This sorts by age in descending order.

Limit results (LIMIT)

SELECT * FROM users
LIMIT 3;

This returns only the top 3 rows.

Now let us change data.