Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     Function groupArray (children 1)
      ExpressionList (children 1)
       Identifier x
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 3)
           ExpressionList (children 1)
            Identifier number (alias x)
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              Function numbers (children 1)
               ExpressionList (children 1)
                Literal UInt64_3
           ExpressionList (children 2)
            OrderByElement (children 1)
             Identifier x
            OrderByElement (children 1)
             Function exp (children 1)
              ExpressionList (children 1)
               Identifier x
    Set
