如何同时显示表格和总成本？答案

【问题标题】：How to show table and total cost together?如何同时显示表格和总成本？
【发布时间】：2016-12-11 00:23:31
【问题描述】：

我正在尝试显示费用列表，并且总费用位于列表底部：

mysql> select   title_name, rental_transaction, renter_lname,renter_fname, rental_cost
    -> from  rentals
    -> where rental_date between '161201' and  '161219'
    -> and  DATEDIFF(date(rental_return_date ), date(rental_date ))  > 7;
+----------------------------+--------------------+--------------+--------------+-------------+
| title_name                 | rental_transaction | renter_lname | renter_fname | rental_cost |
+----------------------------+--------------------+--------------+--------------+-------------+
| WarioWare Touched!         |                 13 | Brennan      | Kathleen     |        2.99 |
| Hot Shots Golf: Open Tee   |                 23 | Grey-Gubler  | Eva          |        3.99 |
| WarioWare Touched!         |                 29 | Smithers     | Kieran       |        2.99 |
| The Urbz: Sims in the City |                 56 | Winters      | Emily        |        4.99 |
| Lumines: Puzzle Fusion     |                 68 | Ryan         | Rebecca      |        3.99 |
| WarioWare Touched!         |                 89 | Byrne        | Ann          |        2.99 |
+----------------------------+--------------------+--------------+--------------+-------------+
6 rows in set (0.00 sec)

我基本上想要这张表格，但我想在表格底部显示租金的总成本，我想知道这是否可行？

【问题讨论】：

老实说，我会在两个单独的查询中执行此操作。

标签： mysql addition

【解决方案1】：

您可以使用UNION 执行此操作。但是由于UNION 需要两个查询具有相同数量的列，您需要添加一些null as columnName

查询：

select   title_name, rental_transaction, renter_lname,renter_fname, rental_cost
from  rentals
where rental_date between '161201' and  '161219'
and  DATEDIFF(date(rental_return_date ), date(rental_date ))  > 7;
union 
select 'total_cost', null as columnName, null as columnName, null as columnName, sum(rental_cost)
from rentals

结果：

【讨论】：