The SELECT command in SQL is a DQL (Data Query Language) command. Other DQL commands include: SHOW and HELP.
Example: display all fields for all records in the vehicles table
SELECT * FROM vehicles;
It should be noted that the word SELECT does not need to be capitalized, but this is a very common way to write SQL statements. It is done to differentiate the SQL keywords (e.g. SELECT, FROM, ORDER BY, INSERT, UPDATE, etc.) from non keywords (e.g. database table names, field names, etc.).
Example: display a particular field for all records in the employees table
SELECT last_name FROM employees;
Example: display a particular field for all records in the employees table sorted by field
SELECT last_name FROM employees ORDER BY last_name;