How to select the last 24 hours from a table with DATATIME column

[ludah]

Please I want get data from mysql; 

1. The last 24 hours. 
2 the last 7 days 
3. the last Months 

4. Last 12 hours

please try and help me

[Barand]

1. SELECT .... FROM tablename WHERE datetimefield > NOW() - INTERVAL 24 HOUR

SELECT .... FROM tablename WHERE datetimefield > NOW() - INTERVAL 7 DAY

SELECT .... FROM tablename WHERE datetimefield > NOW() - INTERVAL 1 MONTH

SELECT .... FROM tablename WHERE datetimefield > NOW() - INTERVAL 12 HOUR

[ludah]

Thank you very much