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Code sample that demonstrates issues with chained filtering
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> from core.models import Application | |
> from django.db.models import Q | |
> test = Q(tags__name__startswith='a') | |
> # Below are two queries that are appear to be the same but are /very/ different | |
> print Application.objects.filter(test).filter(test).filter(test).query | |
SELECT * | |
FROM "application" | |
INNER JOIN "application_tags" ON ( "application"."id" = " application_tags"."application_id") | |
INNER JOIN "tag" ON ("application_tags"."tag_id" = "tag"."id") | |
INNER JOIN "application_tags" T4 ON ("application"."id" = T4."application_id") | |
INNER JOIN "tag" T5 ON (T4."tag_id" = T5."id") | |
INNER JOIN "application_tags" T6 ON ("application"."id" = T6."application_id") | |
INNER JOIN "tag" T7 ON (T6."tag_id" = T7."id") | |
WHERE ( | |
"tag"."name"::TEXT LIKE a % | |
AND T5."name"::TEXT LIKE a % | |
AND T7."name"::TEXT LIKE a % | |
) | |
> print Application.objects.filter(test & test & test).query | |
SELECT * | |
FROM "application" | |
INNER JOIN "application_tags" ON ( "application"."id" = " application_tags"."application_id") | |
INNER JOIN "tag" ON ("application_tags"."tag_id" = "tag"."id") | |
WHERE ( | |
"tag"."name"::TEXT LIKE a % | |
AND "tag"."name"::TEXT LIKE a % | |
AND "tag"."name"::TEXT LIKE a % | |
) |
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