MySQL SELECT last few days?

Use for a date three days ago:

WHERE t.date >= DATE_ADD(CURDATE(), INTERVAL -3 DAY);

Check the DATE_ADD documentation.

Or you can use:

WHERE t.date >= ( CURDATE() - INTERVAL 3 DAY )

You can use this in your MySQL WHERE clause to return records that were created within the last 7 days/week:

created >= DATE_SUB(CURDATE(),INTERVAL 7 day)

Also use NOW() in the subtraction to give hh:mm:ss resolution. So to return records created exactly (to the second) within the last 24hrs, you could do:

created >= DATE_SUB(NOW(),INTERVAL 1 day)

You could use a combination of the UNIX_TIMESTAMP() function to do that.

SELECT ... FROM ... WHERE UNIX_TIMESTAMP() - UNIX_TIMESTAMP(thefield) < 259200