“ALL ROWS” keyword is used to fetch records form recycle bin in Salesforce.

Sample SOQL:

SELECT Id, AccountId 
FROM Contact 
WHERE IsDeleted = true 
ALL ROWS

Execute the below code in Anonymous window to check the results.

Sample Code:

String strQuery = 'SELECT Id FROM Account WHERE IsDeleted = true ALL ROWS';
system.debug( Database.query( strQuery ) );

Another Apex Example:

System.debug(
    'No of deleted PSRs is ' + 
    [
        SELECT COUNT() 
        FROM PendingServiceRouting
        WHERE IsDeleted = true
        ALL ROWS
    ]
);