Question

The documentation for Django QuerySet API explains how to filter results using field lookups. The problem I have is that this approach requires the left hand operand to be a field and I need it to be an expression, to achieve the equivalent of (' ' || tagnames || ' ') LIKE '% xyz %'.

What’s the best way to do this? To clarify what I mean by “best”: I’m hoping for something that will be independent of the actual database used.

Answer 1

One way you can accomplish this is the following (not sure if it’s necessarily the best way):

from django.db.models import Q

...filter(Q(tag_name__startswith=tag_value+' ') | Q(tag_name__contains=' '+tag_value+' ') | Q(tag_name__endswith=' '+tag_value))

Also, you can always just use the actual SQL you’re wanting to use with the raw method.

SomeModel.objects.raw('SELECT * FROM my_table')