Question

我正在尝试创建一个查询，该查询将对按字段分组的结果BY进行分组。我的查询是这样的：

问题是created_by_alias为空的所有行都被分组为一个，这是不好的。我只需要在值与''不同的地方进行分组。

由于某些原因，我无法将字段更改为NULL（网站在joomla上，为了做到这一点，我必须更改核心）。

SELECT c.created_by_alias, c.introtext,c.id,c.publish_up,c.publish_down 
FROM jos_content as c 
GROUP BY c.created_by_alias

这样的事情可能吗？

感谢您的时间和知识：）

示例：

|名字| groupMe |

---------------------------------------
| aaa       |           XX             |
---------------------------------------
| aaa       |           XX             |
---------------------------------------
| ccc       |                          |
--------------------------------------- 
| ddd       |                          |
---------------------------------------

I would like to receive such results:
---------------------------------------
| aaa       |           XX             |
---------------------------------------
| ccc       |                          |
--------------------------------------- 
| ddd       |                          |
---------------------------------------

I hope

Answer 1

  SELECT c.created_by_alias, ...   
  FROM jos_content as c 
  WHERE c.created_by_alias <> ''
  GROUP BY c.created_by_alias
UNION ALL
  SELECT c.created_by_alias, ...   
  FROM jos_content as c 
  WHERE c.created_by_alias = ''

另一种方式是：

  SELECT c.created_by_alias, ...   
  FROM jos_content as c 
  GROUP BY c.created_by_alias
         , CASE WHEN c.created_by_alias = '' 
                  THEN c.PK                  --- the Primary Key
                  ELSE NULL
           END

Answer 2

怎么样？

select name, count(*) from t1
group by name, if (name = '', id, -1)

Answer 3

我可能会忽略你问题中的某些内容，但这不仅仅是一个WHERE - 条件，类似......

SELECT c.created_by_alias, c.introtext,c.id,c.publish_up,c.publish_down 
FROM jos_content as c
WHERE c.created_by_alias != "" 
GROUP BY c.created_by_alias

...

如果我错了，请提供一些示例数据，以便更清楚地了解您要归档的内容。

分组的地方不同于？

示例：

3 个答案: