Re: How to join table to itself N times?

Matt Wilson wrote
> I got this table right now:
>
> select * from market_segment_dimension_values ;
> +--------------------------+---------------+
> | market_segment_dimension |     value     |
> +--------------------------+---------------+
> | geography                | north         |
> | geography                | south         |
> | industry type            | retail        |
> | industry type            | manufacturing |
> | industry type            | wholesale     |
> +--------------------------+---------------+
> (5 rows)

Most likely you can solve your problem by using the "hstore" extension.  I
could be more certain of this if you actually state the
requirements/use-case/business-problem.

SQL requires that you know the column structure of the output so if hstore
does not suffice you will have to execute a dynamic query in your API after
querying the dimension map table to decide how many output columns you will
need.  hstore avoids that by giving you a dynamic table-in-a-column.

David J.



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