Question

我有很多像

这样的表

table tagged ( tid , pid ) 
// its a table to record all product that tagged with.

我有一个过滤字段，可以接受许多标记，然后建议下一个可能标记列表。

这笔交易就像......

when the user filter with tid (1)
The query will search all product tagged with tid 1
then also get others tid that also tagged in returned result
Then group all related tags and order it descendingly

这就是我想要做的，但我迷失了。我已经看过并尝试了关系部门，但我认为我正在尝试的方式更加复杂。

示例基于提供的SQL小提琴。

样本1

Input = tid 1

Desired output 
return list of suggestion In descending which are tid -> 
2 (total amount 7) ,
5 (total amount 4) ,
4 (total amount 3) ,
3 (total amount 1)

样本2

Input = tid 1,2

Desired output 
return list of suggestion In descending which are tid -> 
5 (total amount 3) ,
4 (total amount 1) ,
3 (total amount 1)

以下是我现在唯一返回的所有匹配产品SQL fiddle

Answer 1

我走错路，我实际需要使用的是嵌套选择。

<强>解决方案

SELECT count(tid) FROM tagged 

WHERE pid IN (SELECT pid FROM tagged where tid = 1) AND tid != 1

GROUP BY tid

<强>解释

第一

SELECT pid FROM tagged where tid = 1 //will return full list of product tagged with 1

2RD

SELECT count(tid) FROM tagged WHERE pid IN (1st)
AND tid != 1
//get all tid with return product in 1st query exclude selected tag
GROUP BY tid
//group it so i can sort it

希望能帮到别人。 Solution : nested select

获得许多关系的暗示结果

1 个答案: