SQl Search StoredProcedure

SQl Search StoredProcedure on columns FirstName,LastName,EmailID

Create procedure SearchCustomers
(
@firstname varchar(50),
@LastName varchar(50),
@EmailId varchar(50)
)
As
Begin
 declare @SearchString varchar(1000)
 declare @BuildQuery varchar(50)

 Set @SearchString = 'Select * From Customers' 

 if(@firstname <> '')
  Begin
   set @BuildQuery  = ' FirstName like ''%' + @firstname + '%'''
            
  End
 if(@Lastname<>'')

  Begin
            
   IF(@BuildQuery<>'')
    set @BuildQuery = @BuildQuery + ' and LastName like ''%'+ @LastName +'%'''
   
   Else
   
    set @BuildQuery = @BuildQuery + ' LastName like ''%'+ @LastName +'%'''
   
  END

 if(@EmailId<>'')
        
  Begin
   if(@BuildQuery<>'')
    set @BuildQuery = @BuildQuery +' and EmailId like ''%'+ @EmailId +'%'''
   Else
    set @BuildQuery = @BuildQuery +' EmailId like ''%'+ @EmailId +'%'''
  end
    
 IF(@BuildQuery<>'')
  Begin
            
   Set @SearchString = @SearchString + ' where' + @BuildQuery
  End

    Exec(@SearchString) 

END