Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 2)
     Function toString (alias val) (children 1)
      ExpressionList (children 1)
       Function toString (children 1)
        ExpressionList (children 1)
         Function plus (children 1)
          ExpressionList (children 2)
           Identifier number
           Literal UInt64_1
     Function count (children 1)
      ExpressionList
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function numbers (children 1)
        ExpressionList (children 1)
         Literal UInt64_2
    ExpressionList (children 1)
     OrderByElement (children 1)
      Identifier val
