Question

我希望用现有列名覆盖表中的列名。我正在寻找一种方法来获取表中剩余的未指定列。

注意： 该查询将来可能会有更多的连接。

例如

人

+-----------+----------+---------+
| firstname | lastname | pers_id |
+-----------+----------+---------+
| Joe       | Soap     |       1 |
| Bobby     | Pin      |       2 |
| Janet     | Jackson  |       3 |
+-----------+----------+---------+

分类

+----------+-------------------+--------+
|   type   |    description    | cat_id |
+----------+-------------------+--------+
| customer | people who pay us |      1 |
| employee | people we pay     |      2 |
| director | people who direct |      3 |
+----------+-------------------+--------+

Person_Cat （= ^ェ^ =）

+---------+--------+
| pers_id | cat_id |
+---------+--------+
|       3 |      1 |
|       2 |      2 |
|       1 |      3 |
+---------+--------+

查询

SELECT *, CONCAT(p.firstname, ' '
        , p.lastname) as full_name
        , c.cat_id AS category_id
        ,  p.pers_id AS cat_id
FROM Person AS p 
JOIN Person_Cat AS pc ON(p.pers_id = pc.pers_id) 
JOIN Category AS c ON (pc.cat_id = c.cat_id)

输出（道歉的长度，但后面的表格更重要）

+-----------+----------+---------+---------+--------+----------+-------------------+--------+---------------+-------------+--------+
|      p    |     p    |     p   |    pc   |    pc  |     c    |          c        |    c   |     Select    |    Select   | Select |
+-----------+----------+---------+---------+--------+----------+-------------------+--------+---------------+-------------+--------+
| firstname | lastname | pers_id | pers_id | cat_id |   type   |    description    | cat_id |   full_name   | category_id | cat_id |
+-----------+----------+---------+---------+--------+----------+-------------------+--------+---------------+-------------+--------+
| Janet     | Jackson  |       3 |       3 |      1 | customer | people who pay us |      1 | Janet jackson |           1 |      3 |
| Bobby     | Pin      |       2 |       2 |      2 | employee | people who we pay |      2 | Bobby Pin     |           2 |      2 |
| Joe       | Soap     |       1 |       1 |      3 | director | people who direct |      3 | Joe Soap      |           3 |      1 |
+-----------+----------+---------+---------+--------+----------+-------------------+--------+---------------+-------------+--------+

列名称上方的标题可供参考到他们来自哪里。

列摘要 -

firstname，lastname，pers_id，pers_id，cat_id，type，

description，cat_id，full_name，category_id，cat_id

通缉输出

+-----------+----------+---------+--------+----------+-------------------+---------------+-------------+--------+
|      p    |     p    |    pc   |    pc  |     c    |          c        |     Select    |    Select   | Select |
+-----------+----------+---------+--------+----------+-------------------+---------------+-------------+--------+
| firstname | lastname | pers_id | cat_id |   type   |    description    |   full_name   | category_id | cat_id |
+-----------+----------+---------+--------+----------+-------------------+---------------+-------------+--------+
| Janet     | Jackson  |       3 |      1 | customer | people who pay us | Janet jackson |           1 |      3 |
| Bobby     | Pin      |       2 |      2 | employee | people who we pay | Bobby Pin     |           2 |      2 |
| Joe       | Soap     |       1 |      3 | director | people who direct | Joe Soap      |           3 |      1 |
+-----------+----------+---------+--------+----------+-------------------+---------------+-------------+--------+

列摘要 -

firstname，lastname，pers_id，cat_id，type，

description，full_name，category_id，cat_id

注意： p.pers_id 和 c.cat_id 不存在。我想这是因为与ConCat中使用的first和lastname不同，它们被直接调用并且未被修改

Answer 1

如果简短回答是目前没有Select [remaining columns]这样的概念（2015-06-17），如果您想使用SELECT *但只删除多余的列< / strong>下，然后，您需要在渲染视图时显式删除（忽略）这些冗余列。

您必须显式配置要忽略哪些列的逻辑，这与显式列出您感兴趣的列几乎相同，因此您将回到参数，而不是选择我在以上评论。

除非您的表架构一直在更改，否则实际上没有理由这样做。

如何选择剩余的未指定列

1 个答案: