Get last 30 day records from today date in SOQL

SOQL queries in a Salesforce database.

How do you query the database and only get back the results up to a certain time period.  Example:  I want the records from the last 30 days or the past 6 months.

Better yet, how do we do this in SOQL

Answer:

1 Select * from case WHERE CreatedDate = LAST_N_DAYS:30

Resource:

https://developer.salesforce.com/forums/?id=906F00000008mk6IAA