Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function sum (children 1)
      ExpressionList (children 1)
       Function plus (children 1)
        ExpressionList (children 2)
         Literal Float64_2.11
         Identifier uint64
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table
