从SQL中选择项目集 [英] Select itemset from SQL
问题描述
嘿伙计们,
我不是最强大的SQL开发人员,我只是快速询问是否有可能。
我有下表:
项目集
itemsetid productid
| 1 | 5 |
| 1 | 6 |
| 2 | 5 |
| 2 | 9 |
我想做的是返回所有项目集并知道有多少项目集。
我要归还的内容:
[[1(5,6)],[2(5,9)]] - > ;这长度= 2(项目集数量)
这些内容。
任何帮助都是非常感谢,
谢谢
Hey guys,
I am not the strongest SQL developer, I just have a quick question checking if this is possible.
I have the following table:
Itemsets
itemsetid productid
| 1 | 5 |
| 1 | 6 |
| 2 | 5 |
| 2 | 9 |
What I want to do is return all the itemsets and know how many are there.
What I want returned:
[[1(5,6)],[2(5,9)]] -> length of this = 2(number of itemsets)
Something along these lines.
Any help is greatly appreciated,
Thanks
推荐答案
select itemsetid, count(1) from itemsets group by itemsetid
这会给你
1 2
2 2
this will give you
1 2
2 2
这是一项特殊要求,我建议你为此制作代码。
您有3种可能性( http: //www.codeguru.com/cpp/data/mfc_database/misc/article.php/c12615/MySQL-UDFs.htm [ ^ ]):
- 存储过程 [ ^ ]
- UDF
- 本机功能
这取决于您的编程知识以及您对服务器的访问权限。如果您需要快速处理并且可以使用C编写它并将UDF部署到服务器,请执行此操作。如果没有,请编写存储过程。
This is a special requirement, I suggest you make code for that.
You have 3 possibilities (http://www.codeguru.com/cpp/data/mfc_database/misc/article.php/c12615/MySQL-UDFs.htm[^]):
- Stored procedure[^]
- UDF
- Native function
It depends on your programming knowledge and the access you have to the server. If you need fast processing and you can write it in C and deploy the UDF to the server, do it. If not, write a stored procedure.
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