join - MySQL - get elements from a link table but ONLY those elements -

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There is a problem with selecting a link from the table and filtering out more than enough results.

Publication relates to Package via the Package_Publication table. For example, I know of my publications being ID 11 and 47. I want to return a package which is only in those publications.

Now if I join one and do something like then publication.id IN (11, 47) after the obvious internal joins, it only returns all those packages Which will be one of those values ​​in the package_publications link table.

I want to match those packages in which only both (or more - it is not limited to two). Effectively I want one or the other when I am using, but I do not know how to contact it with SQL-wise.

Your best bet is a correlated subquery. The second option is associated with different groups but it Not performing well, especially on the big table.

Subkey: 

  SELECT * `packages` WHERE 2 = (`number of selects (*) from` package_publications` where`` package_. id = `package_publications`.package_id And `package_public publication`. Publication_id IN (11, 47))

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