Just add a WHERE clause to the query I put in a previous post. Change dates as appropriate.

Code
DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME

SET @StartDate = '1/1/2017'
SET @EndDate = '4/1/2017'

SELECT Demographics.PatientID, [Last] as LastName, [First] as FirstName, Gender, BirthDate, Phone FROM Demographics INNER JOIN 
(SELECT DISTINCT PatientID FROM Billing WHERE DateOfService BETWEEN @StartDate AND @EndDate) as a on Demographics.PatientID = a.PatientID 
WHERE phone is null or phone = ''
ORDER BY LastName

JamesNT

James Summerlin
My personal site: http://www.dataintegrationsolutions.net
james@dataintegrationsolutions.net