SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function in (children 1)
     ExpressionList (children 2)
      Literal Tuple_(UInt64_1, \'a\')
      Function tuple (children 1)
       ExpressionList (children 3)
        Literal Tuple_(UInt64_1, \'a\')
        Literal Tuple_(UInt64_2, \'b\')
        Literal Tuple_(UInt64_3, \'c\')