Re: Populate Table From Two Other Tables

SQL does not distinguish between equality and assignment (mainly because SQL
is declarative and thus there is never anything to actually assign to). IOW,
there is not "assignment" operator and "=" means "equality".

As for the duplicate key I would first check to see if you are inserting
into a non-empty table and that one or more of your newly inserted records
conflicts with existing records on the waterchem table. The easiest way
would be to insert into a staging table and then join the staging and live
tables together on the PK and see if any records are returned.

David J.

> -----Original Message-----
> From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-
> owner(at)postgresql(dot)org] On Behalf Of Rich Shepard
> Sent: Tuesday, June 05, 2012 7:28 PM
> To: pgsql-general(at)postgresql(dot)org
> Subject: Re: [GENERAL] Populate Table From Two Other Tables
>
> On Tue, 5 Jun 2012, Greg Williamson wrote:
>
> > Try a single equals sign, e.g. WHERE c.site = s.siteid
>
> Greg,
>
> I'm surprised: that worked! I thought the WHERE clause was looking for
> equivalency, not an assignment.
>
> There's another problem now that will be more difficult to fix.
Postgres tells
> me, 'psql:populate-waterchem.sql:6: ERROR: duplicate key value violates
> unique constraint "waterchem_pkey"'. But, when I SELECT rows based on
> the primary key only a single row is returned.
>
> I think the most parsimonious solution is to use an awk script to add
the
> stream and basin columns to the chemistry.txt file. That also eliminates
> having to export the combined table to a text file.
>
> Thanks,
>
> Rich
>
>
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