Is it possible to define dynamic projections in Slick?

Question

I have a query joining many tables. I would like to be able to parameterize which fields to retrieve (sometimes complex SQL Postgis functions). Let say that the initial request is constructed as follows:

def buildQuery() = for {
  c <- coffees if c.price > 9.0
  s <- c.supplier
} yield (c.name, s.name)

Now I want one of the received values ​​to depend on my parameter, so the example will look like this:

val param = true
def buildQuery() = for {
  c <- coffees if c.price > 9.0
  s <- c.supplier
} yield (c.name, if (param) s.name else null)

Such code will not work; internal Slick objects raise a NullPointerException. Is there a reasonable way to dynamically build part of the yield based on input parameters?

Answer 1

, slick "case dsl": https://github.com/slick/slick/blob/master/src/main/scala/scala/slick/lifted/Case.scala