mysql - Inverse of Inner join (Intersect) with multiple foreign keys -
hi want opposite of intersect 2 tables.
i have sale table , purchase table. want purchases ids not included in sales table.
sale table
sale_id (pk)
product_id (fk)
purchase_id (fk)
purchase table
product_id (fk)
purchase_id (pk)
select distinct purchase_id , product_id purchase inner join sale using (purchase_id, product_id);
here example: if run above code, result.
purchase_id product id 1 1 1 2 1 4 2 1 2 3
now want get:
purchase_id product id 1 3 2 2
in short want inverse of above code. in advance.
okay, think understand better now.
this should return entry in purchase have no matching entry in sales.
select `purchase`.`purchase_id`, `purchase`.`product_id` `purchase` left join `sale` on `sale`.`purchase_id` = `purchase`.`purchase_id` , `sale`.`product_id` = `purchase`.`product_id` `sale`.`sale_id` null order `purchase`.`purchase_id`, `purchase`.`product_id`
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