Hi there I have three linked tables, the_data (with the actual data I want), linked with an nn_link table to a category table. Then, that category table is linked n:1 to a display_category table.
The other way around: Each display_category entry is linked to one category entry, which in turn is linked to several the_data entries (n:n). I hope that just made sense :-) Now I want to extract all the_data entries that are in all of a list of display_category entries (because those display_category entries are hierarchically ordered as well). For example, when I display the category 1->2->3 in that hierarchical order, I want to display all the entries that are in the display_category-ies 1, 2 and 3. What I managed to do so far though is just to extract all the entries that are in one of those categories... select * from ((( the_data inner join nn_link on the_data.id = nn_link.the_data_id ) inner join category on category.id = nn_link.category_id ) inner join display_category on category.id = display_category.category_id ) where display_category.id in (1, 2, 3); I tried with a group by as well: select * from ((( the_data inner join nn_link on the_data.id = nn_link.the_data_id ) inner join category on category.id = nn_link.category_id ) inner join display_category on category.id = display_category.category_id ) group by the_data.id having display_category.id in (1, 2, 3) and count(the_data.id) = 3; But unfortunately, I don't understand the results, even with help of the "explain" output - the counts were higher than I anticipated, I thought they would just represent the number of possible paths towards a the_data entry... Thanks in advance for your kind help Guido -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]