Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function plus (children 1)
      ExpressionList (children 2)
       Function minus (children 1)
        ExpressionList (children 2)
         Function multiply (children 1)
          ExpressionList (children 2)
           Literal UInt64_2
           Function count (children 1)
            ExpressionList (children 1)
             Identifier float64
         Function sum (children 1)
          ExpressionList (children 1)
           Identifier float64
       Function minus (children 1)
        ExpressionList (children 2)
         Function multiply (children 1)
          ExpressionList (children 2)
           Literal UInt64_3
           Function count (children 1)
            ExpressionList (children 1)
             Identifier float64
         Function sum (children 1)
          ExpressionList (children 1)
           Identifier float64
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table
