Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function avg (children 1)
      ExpressionList (children 1)
       Function multiply (children 1)
        ExpressionList (children 2)
         Identifier number
         Function log (children 1)
          ExpressionList (children 1)
           Literal UInt64_2
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function numbers (children 1)
        ExpressionList (children 1)
         Literal UInt64_10
