Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function minus (children 1)
      ExpressionList (children 2)
       Function sum (children 1)
        ExpressionList (children 1)
         Function plus (children 1)
          ExpressionList (children 2)
           Identifier uint64
           Literal UInt64_2
       Function sum (children 1)
        ExpressionList (children 1)
         Function plus (children 1)
          ExpressionList (children 2)
           Identifier uint64
           Literal UInt64_3
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table
