DescribeQuery (children 1)
 TableExpression (children 1)
  Subquery (children 1)
   SelectWithUnionQuery (children 1)
    ExpressionList (children 1)
     SelectQuery (children 2)
      ExpressionList (children 1)
       Function concat (children 1)
        ExpressionList (children 2)
         Function concat (children 1)
          ExpressionList (children 2)
           Function toString (children 1)
            ExpressionList (children 1)
             Identifier id
           Literal \'_\'
         Identifier value
      TablesInSelectQuery (children 1)
       TablesInSelectQueryElement (children 1)
        TableExpression (children 1)
         TableIdentifier test_table