Question

I have an SP. It returns some number of rows. Here is the SP:

ALTER PROCEDURE [dbo].[spGetClients]

(
@orderBy varchar(50),
@startAge int,
@endAge int,
@sex char,
@staffId nvarchar(1024),
@statusId nvarchar(1024),
@ethnicityId nvarchar(1024),
@treatmentProviderId nvarchar(1024)
)
AS
BEGIN
SET NOCOUNT ON;

IF(@orderBy = 'Consumer Name')
BEGIN
    SELECT c.Id, dbo.GetClientFullName(c.FirstName, c.MiddleInit, c.LastName) AS ClientName, 
    c.DateOfBirth, dbo.GetAge(c.DateOfBirth, GETDATE()) AS Age, c.Sex, 
    dbo.GetClientStatus(c.Id, @statusId) AS Status, ca.Address, co.Phone, 
    dbo.GetEthnicity(c.Id, @ethnicityId) AS Ethnicity, dbo.GetDevelopmentalDisabilities(c.Id) AS Disabilities, 
    dbo.GetClientStaffContacts(c.Id, @staffId) AS Staff, dbo.GetClientContacts(c.Id) AS Contact, 
    dbo.GetClientInsuranceProviders(c.Id) AS HealthProvider, 
    dbo.GetClientTreatmentProviders(c.Id, @treatmentProviderId) AS TreatmentProvider
    FROM Client c  
    LEFT OUTER JOIN(        
        SELECT ca.ParentEntityId, ca.Address
        FROM ContactAddress ca
        INNER JOIN EntityName en ON en.Id = ca.EntityNameId AND en.Name = 'Client' 
        INNER JOIN GeneralLookup gl ON ca.glAddressTypeId = gl.Id AND gl.LookupItem = 'Primary'    
    ) ca ON c.Id = ca.ParentEntityId 
    LEFT OUTER JOIN(        
        SELECT co.ParentEntityId, co.ContactData Phone
        FROM ContactOther co
        INNER JOIN EntityName en ON en.Id = co.EntityNameId AND en.Name = 'Client' 
        INNER JOIN GeneralLookup gl ON co.glContactTypeId = gl.Id AND gl.LookupItem = 'Home'    
    ) co ON c.Id = co.ParentEntityId 
    LEFT OUTER JOIN GeneralStatus gs on gs.Id = c.StatusId
    where gs.Name <> 'Deleted' 
    and (dbo.GetAge(c.DateOfBirth, GETDATE()) BETWEEN @startAge and @endAge)
    and ((@sex = 'M' and c.sex = 'M') or (@sex = 'F' and c.Sex = 'F') or (@sex = '' and (c.Sex in ('M', 'F', ''))))
    and dbo.GetClientStaffContacts(c.Id, @staffId) is not null
    and dbo.GetClientStaffContacts(c.Id, @staffId) is not null
    and dbo.GetClientStatus(c.Id, @statusId) is not null 
    and dbo.GetEthnicity(c.Id, @ethnicityId) is not null 
    and dbo.GetClientTreatmentProviders(c.Id, @treatmentProviderId) is not null
    ORDER BY ClientName
END
END

The UDFs(User defined functions) are dbo.GetClientStaffContacts(c.Id, @staffId) and other. They return some rows which are having null as well. That’s why I’m using last 5 statements in where clause so that only non null values can be collected. Everything is working fine but the problem is, I want this check of non null only when these variables are NOT empty string:

@staffId nvarchar(1024), 
@statusId nvarchar(1024), 
@ethnicityId nvarchar(1024), 
@treatmentProviderId nvarchar(1024)

How can I resolve this issue?
I want something like this:

If @staffId <> '' then dbo.GetClientStaffContacts(c.Id, @staffId) is not null

Answer 1

 AND  ((@staffId = "") OR (dbo.GetClientStaffContacts(c.Id, @staffId) is not null))