how can i create a tagging system using php and mysql?

Question

wondering how i can create a tagging system in php and with a mysql database, my initial thoughts were to create a row in the table where the articles are stored, named tags, and list the tags seperated by commas, but i am not sure how i can create a query that searches for matching tags, i dont want to have to query every article everytime someone clicks a tag. can anyone help?

Answer 1

You're describing a many-to-many relationship between Articles and Tags. You'd want to use an intermediate junction table to resolve that relationship.

Now, to find all articles that match a selected tag:

SELECT a.article_title
    FROM Tag t
        INNER JOIN Article_Tag_Xref atx
            ON t.tag_id = atx.tag_id
        INNER JOIN Article a
            ON atx.article_id = a.article_id
    WHERE t.tag_name = 'SelectedTagName'

Answer 2

tbl_articles has articleID, etc.

tbl_tags has tagID, etc.

tbl_taggedarticles has taggedArticleID, articleID, tagID

SELECT articleID FROM tbl_taggedarticles WHERE tagID = "searchedID"