sql - Ignore other results if a resultset has been found -

to start, take snippet example:

select *  statsvehicle  ((referencemakeid = @referencemakeid)  or @referencemakeid null) 

this fetch , filter records if variable @referencemakeid not null, , if null, fetch records. in other words, taking first 1 consideration if @referencemakeid not null.

i add further restriction this, how can achieve this?

for instance

(referencemodelid = @referencemodeleid) or (     (referencemakeid = @referencemakeid) or     (@referencemakeid null) ) 

if @referencemodelid not null, need filter referencemodelid, , ignore other statements inside it. if such, returns records. there can done achieve such thing?

maybe this?

select * statsvehicle  (      -- removed following, it's not clear if beneficial     -- (@referencemodeleid not null) ,      (referencemodelid = @referencemodeleid) ) or (@referencemodeleid null ,   (     (referencemakeid = @referencemakeid) or     (@referencemakeid null)  ) )