SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function toFixedString (children 1)
     ExpressionList (children 2)
      Literal \'--- Int Empty ---\'
      Function toLowCardinality (children 1)
       ExpressionList (children 1)
        Literal UInt64_17
    Function arrayReduce (children 1)
     ExpressionList (children 2)
      Function toNullable (children 1)
       ExpressionList (children 1)
        Literal \'avgOrNull\'
      Literal Array_[UInt64_1]
