[Answered ]-How to apply a filter for each row of the same queryset on Django

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1👍

Save for one syntax error (square brackets rather than parentheses after values_list) this should work as you intended.

This induces only a single query. Note you can check the SQL that the ORM generates by accessing the .query property of the queryset (the following was subsequently run through a SQL pretty-printer):

>>> str(qs.query)
SELECT
    "yourapp_product"."id",
    "yourapp_product"."parent_id",
    "yourapp_product"."stock",
    SUM((SELECT U0."stock" FROM "yourapp_product" U0 WHERE U0."parent_id" = (U0."id"))) AS "stock_sum"
FROM
    "yourapp_product"
WHERE
    "yourapp_product"."is_parent"
GROUP BY
    "yourapp_product"."id",
    "yourapp_product"."parent_id",
    "yourapp_product"."stock";
👤Daniel W. Steinbrook

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