SELECT * FROM tbl WHERE col>=DATEADD(year,-1,GETDATE())
SELECT * FROM tbl WHERE col>=DATEADD(month,-3,GETDATE())
SELECT * FROM tbl WHERE col>=DATEADD(day,-7,GETDATE())
SELECT * FROM tbl WHERE col>=DATE_ADD(NOW(), interval -1 year)
SELECT * FROM tbl WHERE col>=DATE_ADD(NOW(), interval -3 month)
SELECT * FROM tbl WHERE col>=DATE_ADD(NOW(), interval -7 day)