Add An Example For .extra(tables=[])

[Mike Shultz]

When fiddling around trying to find a solution to one of my problems, it seems to be that .extra(tables=[]) was what I needed. I took a trip through the django documentation just to find that there were no examples, or even a description into what kind of 'string' it takes. Is it JOIN statements? Just a name of a table and/or matching columns?

Please add an example to the documentation and/or a better explanation of the string it accepts.

Reference: ​http://docs.djangoproject.com/en/dev/ref/models/querysets/#extra-select-none-where-none-params-none-tables-none-order-by-none-select-params-none

[Gabriel Hurley]

Agreed. There is an example for where, but not for tables. Adding this would be helpful.

[John Paulett]

Add example using both tables and where in Queryset.extra()

[John Paulett]

Attached a patch to add this documentation. The example is fairly trivial (in fact, it makes more sense as a simple filter())

[Chris Beaven]

The example follows the bad practice of embedding values in the where clause rather than in params

It'd also be better if the example was hypothetically useful.

[Bernhard Essl]

Added a patch with params using in the where clause.

[Christopher Medrela]

Is this note necessary? I can't find any useful example of using extra(where=...) - everything can be done with objects.filter. I suggest to close this ticket.

[James Aylett]

The documentation now explains what format tables should be in. I suspect that the only uses of this are fairly complex, and so the effort in explaining the context in documentation is going to outweigh the value of an actual example.

[Tim Graham]

Agreed with the last two comments, if we can't come up with a useful example here I don't see much use in adding this.