mysql - How to query 2 tables relation of which is described by another pk to pk table? -


i have db of 3 tables: categories, items, relation. categories contain categories. goods stored in items , relation binding table, stores product id , category id or categories.

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how can given list of items, names of categories?

you can try left join this.

select     *     items left join relation r on i.id = r.id_items left join categories c on r.id_cat = c.id

hope helps.

above query give items note mapped in relation table while below query give items has defined relation in table relation 

select     *     items right join relation r on i.id = r.id_items left join categories c on r.id_cat = c.id

let me know if error.


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