SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function greatest (children 1)
     ExpressionList (children 2)
      Function toLowCardinality (children 1)
       ExpressionList (children 1)
        Literal UInt64_1
      Literal NULL
    Function least (children 1)
     ExpressionList (children 2)
      Function toLowCardinality (children 1)
       ExpressionList (children 1)
        Literal UInt64_1
      Literal NULL
