MySQL Query: Filtering search results by tags -


suppose have database table works link between 2 others. in case, link between book , tag, such "fiction" or "gardening". if have following dataset:

book_id | tag_id ---------------- 1       | 13 1       | 43 1       | 15 2       | 13 2       | 25

what kind of query run "find books have links tags 13, 43, , 15"? is, more tags add, smaller number of books shown.

i hope makes sense. in advance time , help!!

try this

select   book_id   book_tags group   book_id having    sum( case when tag_id in (13, 43, 15) 1 end ) >= 3

you need books have tags 13, 43, 15 (all of them), returns book_id = 1 result. sum() >= 3 specifies total number of tags searching, in case 3, i.e 13, 43, 15

sqlfiddle


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