What does the '*' symbol mean in the SELECT statement when executing an SQL query?

The * symbol in the SELECT statement in SQL means selecting all columns from the specified table or set of tables. Instead of listing each column by name, SELECT * returns all columns.

For example:

SELECT * FROM users;

This query will return all fields of all records from the users table. It is convenient for quickly obtaining all data, but in production, it is better to explicitly specify the needed columns for optimization and security.