[sql] How to select data from 30 days?

I have query:

SELECT name
FROM (
SELECT name FROM 
Hist_answer
WHERE id_city='34324' AND datetime >= DATE_SUB(CURRENT_DATE, INTERVAL 1 MONTH)
UNION ALL
SELECT name FROM 
Hist_internet
WHERE id_city='34324' AND datetime >= DATE_SUB(CURRENT_DATE, INTERVAL 1 MONTH)
) x
GROUP BY name ORDER BY name

But DATE_SUB is a MySQL function and I need function for MsSQL 2008

Tell me please how to select data from 30 days by using MsSQL 2008?

P.S.: Data type of datetime is smalldatetime

Short version for easy use:

SELECT * 
FROM [TableName] t
WHERE t.[DateColumnName] >= DATEADD(month, -1, GETDATE())

DATEADD and GETDATE are available in SQL Server starting with 2008 version. MSDN documentation: GETDATE and DATEADD.

For those who could not get DATEADD to work, try this instead: ( NOW( ) - INTERVAL 1 MONTH )

Try this : Using this you can select date by last 30 days,

SELECT DATEADD(DAY,-30,GETDATE())