Querying All Records with a SOQL Statement

SOQL statements can use the ALL ROWS keywords to query all records in an organization, including deleted records and archived activities. For example:
System.assertEquals(2, [SELECT COUNT() FROM Contact WHERE AccountId = a.Id ALL ROWS]);

You can use ALL ROWS to query records in your organization's Recycle Bin. You cannot use the ALL ROWS keywords with the FOR UPDATE keywords.