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Re: BUG #7543: Invalid table alias: DELETE FROM table *

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: barrybrown(at)sierracollege(dot)edu
Cc: pgsql-bugs(at)postgresql(dot)org, pgsql-docs(at)postgresql(dot)org
Subject: Re: BUG #7543: Invalid table alias: DELETE FROM table *
Date: 2012-09-17 03:58:06
Message-ID: 5536.1347854286@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-bugspgsql-docs
barrybrown(at)sierracollege(dot)edu writes:
> I sometime see my users delete all rows from a table using a command like
> this:

> DELETE FROM customer *;

> The question is: what is the star? Is it a table alias or an
> output_expression?

Neither; it specifies to search the table and its inheritance children,
ie, the opposite of ONLY.  This has been the default behavior (unless
you change the setting of sql_inheritance) for many years, so "*" has
largely fallen into disuse; but it's still accepted.

However ... I went looking for documentation on this point, and I'm
darned if I can find any.  There certainly used to be some, but
apparently somebody got over-eager about editing the docs to reflect
the modern default behavior.  The "*" doesn't even appear in the syntax
summaries for most of the commands where it's allowed, which is flat
wrong --- anywhere you can write "ONLY tablename", it's valid to write
"tablename*" instead.

So we have some docs work to do.  Thanks for pointing it out.

			regards, tom lane


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