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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <bruce@momjian.us>
cc: pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: doc: add examples of creative use of unique expression
 indexes
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Comments: In-reply-to Bruce Momjian <bruce@momjian.us>
	message dated "Fri, 10 Apr 2020 17:48:21 -0400"
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Bruce Momjian <bruce@momjian.us> writes:
> I agree with your analysis.  I still want to have some mention that
> partial indexes can be used to create single-NULL columns, which might
> be required for compatibility with other databases.  Attached is an
> updated patch which removes the previous commit but adds a mention of
> this.

The single-null thing is probably a useful example, but please make
it an actual separate example, or at least its own para outside the
existing <example> sections.

Also, the existing example demonstrating that seems overcomplicated;
why not just

    create unique index ... (1) where (foo is null);

			regards, tom lane