The SELECT keyword is used at the beginning of a SOQL query to define which fields you want to retrieve from an sObject. The basic syntax for a SELECT statement is:

SELECT AccountNumber
FROM Account 

This query retrieves the Account Number from every Account record in Salesforce. When writing a SELECT statement, notice that we're referencing the field's API Name, not the label.

When we want to retrieve more than one field, we separate them with a , comma. Let's also retrieve the Accounts' Name and Website:

SELECT Name, AccountNumber, Website
FROM Account 

Similarly, we can retrieve the Name, Birthday, and Email fields from Contact:

SELECT Name, Email, Birthdate
FROM Contact 

Or Opportunity, with its custom OrderNumber__c field:

SELECT Name, StageName, ExpectedRevenue, OrderNumber__c
FROM Opportunity