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
