Based on MaybeFilter (https://gist.github.com/cvogt/9193220), it uses implicit class to add the methods to the Query objects. FilteredBy works for filtering lists and it returns the query if no filters were applied. FoundBy works for finding a single register, if no filter defined it returns None.

OptionFilter.scala

implicit class OptionFilter[ X, Y ]( query: Query[ X, Y, Seq ] ) {
  def filteredBy[ T ]( op: Option[ T ] )( f: ( X, T ) => Column[ Option[ Boolean ] ] ): Query[ X, Y, Seq ] = {
    op map { o => query.filter( f( _, o ) ) } getOrElse { query }
  }

  def foundBy[ T ]( op: Option[ T ] )( f: ( X, T ) => Column[ Option[ Boolean ] ] ): Query[ X, Y, Seq ] = {
    op map { o => query.filter( f( _, o ) ) } getOrElse { query.take( 0 ) }
  }
}