The ‘STORED PROCEDURE’ Content

CREATE PROC spRegistry_PersonsGetField
@ID int,@Field varchar(100)
AS
SELECT CASE @Field 
WHEN 'Name' THEN Name
WHEN 'Surname' THEN Surname
WHEN 'Username' THEN Username
WHEN 'Password' THEN Password
WHEN 'Status' THEN dbo.fnStatus(Status)
WHEN 'EMail' THEN EMail
WHEN 'Tel' THEN dbo.fnIsEmpty(Tel)
WHEN 'Address' THEN dbo.fnIsEmpty(Address)
WHEN 'City' THEN dbo.fnIsEmpty(City)
WHEN 'BirthDate' THEN dbo.fnDate(BirthDate)
WHEN 'Gender' THEN dbo.fnGender(Gender)
WHEN 'Lang' THEN Lang
ELSE NULL
END
AS [Alan] varchar(200)
FROM Registry_Persons
WHERE ID = @ID

我的查询

EXEC spRegistry_PersonsGetField 1,‘BirthDate’

错误消息

Conversion Failed when converting the varchar value ’04/11/2011′ to data type int.