Django kwargs expansion not working with startswith

Question

I was facing a problem very similar to question 310732 and following the advice there, I implemented the .format() solution in my kwargs generation.

A dump of a small example looks like this:

{'username_fragment_1__startswith': u'joey'}

where "username_fragment_1" is a valid column name.

More details per Daniel's request:

query_sub = "(CASE WHEN ISNULL(%s) THEN 0 ELSE LENGTH(%s) END)"

query_string = query_sub % ((label_dict[frag],)*2)

results[frag] = DisplayNameSearchResult.objects.filter(**kwargs).extra(select={ 'proxylen':(query_string)},order_by=['proxylen']).values('agent_id', 'proxylen')

However, when I run the unit tests, I get:

OperationalError: (1054, "Unknown column 'username_fragment_1__startswith' in 'field list'")

The call in views.py looks something like:

MyClass.objects.filter(**kwargs)

Suggestions appreciated.

Please show the exact call, rather than one that "looks something like" it. — Daniel Roseman, Mar 10 '15 at 07:31
can you try removing `extra(select={ 'proxylen':(query_string)},order_by=['proxylen']).values('agent_id', 'proxylen')`, see if it works? — eugene, Mar 10 '15 at 15:16
@eugene: Yeah, I tried that too, at the time. The processing failed at the filter, so it never even got to the extra part. — coyot, Mar 11 '15 at 14:33

score 0 · Accepted Answer · answered Mar 10 '15 at 16:04

0

And now, this morning it is working with no changes. Closing as a heisenbug.

answered Mar 10 '15 at 16:04

coyot

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Django kwargs expansion not working with startswith

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