Thanks, Sebastian!
I have tried this one before. The problem is that it finds all items
the tags of which include EITHER 'blue' OR 'red', not 'blue' AND 'red':
mysql> SELECT DISTINCT items.title from items inner join taggings on
(items.id = taggings.item_id) inner join tags on (tags.id =
taggings.tag_id) WHERE tags.name IN ('red', 'blue');
+-------------------------------+
| title |
+-------------------------------+
| tagged_red |
| tagged_red_and_blue |
| tagged_red_and_green |
+-------------------------------+
Do you have an idea how to create an AND query?
Ingo
On Apr 22, 2008, at 5:42 PM, Sebastian Mendel wrote:
> Ingo Weiss schrieb:
>> Hi all,
>>
>> I have an application where items can be tagged. There are three
>> tables
>> 'items', 'taggings' and 'tags' joined together like this:
>>
>> items inner join taggings on (items.id = taggings.item_id) inner join
>> tags on (tags.id = taggings.tag_id)
>>
>> Now I have been struggling for some time now with coming up with
>> the SQL
>> to find the items the tags of which include a specified list of tag
>> names. Example:
>>
>> I am looking for items tagged with 'blue' and 'red'. This should
>> find me:
>>
>> - items tagged with 'blue' and 'red'
>> - items tagged with 'blue', 'red' and 'green'
>
> SELECT DISTINCT items.*
> FROM [your join above]
> WHERE tags.name IN ('blue', 'red');
>
> --
> Sebastian Mendel
