SEARCH Employee table based on EXACT Date of Birth or PARTIAL Date of Birth

Hi all,

I have a scenario where I would like to retrieve a record from EMPLOYEE table based on our end users enter the EXACT Date of Birth or just a partial Date of Birth.

I am able to retrieve a record when our end users enter the EXACT DOB (09-15-1960) but when our end users enter a partial DOB (just "YYYY" 1960), then I don't have any records returned.

The following is my WHERE clause:

note: vp.DOB is DATETIME field.

DECLARE @DOB DATETIME
DECLARE @DOB_YYYY DATETIME
DECLARE @DOB_MM DATETIME
DECLARE @DOB_DD DATETIME

SET @DOB = NULL
SET @DOB_YYYY = '1960'
SET @DOB_MM = NULL
SET @DOB_DD = NULL

 
SELECT DISTINCT TOP (5000) 

  dbo.fnGetDisplayName(vp.LastOrBusinessName,vp.FirstName, vp.MiddleName, vp.SuffixName) as [Name],
  dbo.fnGetDisplayNameByPartyID(vp.FirstPlaintiffID) as Plaintiff

FROM
	tblEmployee vp WITH (NOLOCK) 
	  
WHERE 
-- Search by DOB
(vp.DOB = @DOB OR @DOB IS NULL)
AND
((SELECT YEAR(vp.DOB)) = @DOB_YYYY)

Any help is greatly appreciate it.

THANK YOU!